Auto merge of #18670 - avadacatavra:interactive-metrics, r=jdm

added time to interactive metrics

<!-- Please describe your changes on the following line: -->

Added time to interactive metrics and refactored metrics/lib

I need to write tests, but wanted to submit the PR for review

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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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Cargo.lock

@@ -1820,10 +1820,13 @@ dependencies = [
  "gfx_traits 0.0.1",
  "ipc-channel 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "malloc_size_of 0.0.1",
+ "malloc_size_of_derive 0.0.1",
  "msg 0.0.1",
  "profile_traits 0.0.1",
  "script_traits 0.0.1",
  "servo_config 0.0.1",
+ "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

components/layout_thread/lib.rs

@@ -86,7 +86,7 @@ use layout::wrapper::LayoutNodeLayoutData;
 use layout_traits::LayoutThreadFactory;
 use libc::c_void;
 use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
-use metrics::{PaintTimeMetrics, ProfilerMetadataFactory};
+use metrics::{PaintTimeMetrics, ProfilerMetadataFactory, ProgressiveWebMetric};
 use msg::constellation_msg::PipelineId;
 use msg::constellation_msg::TopLevelBrowsingContextId;
 use net_traits::image_cache::{ImageCache, UsePlaceholder};

components/metrics/Cargo.toml

@@ -14,7 +14,10 @@ gfx = {path = "../gfx"}
 gfx_traits = {path = "../gfx_traits"}
 ipc-channel = "0.9"
 log = "0.3.5"
+malloc_size_of = { path = "../malloc_size_of" }
+malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 msg = {path = "../msg"}
 profile_traits = {path = "../profile_traits"}
 script_traits = {path = "../script_traits"}
 servo_config = {path = "../config"}
+time = "0.1"

components/metrics/lib.rs

@@ -7,10 +7,14 @@ extern crate gfx_traits;
 extern crate ipc_channel;
 #[macro_use]
 extern crate log;
+extern crate malloc_size_of;
+#[macro_use]
+extern crate malloc_size_of_derive;
 extern crate msg;
 extern crate profile_traits;
 extern crate script_traits;
 extern crate servo_config;
+extern crate time;
 
 use gfx::display_list::{DisplayItem, DisplayList};
 use gfx_traits::Epoch;
@@ -18,56 +22,217 @@ use ipc_channel::ipc::IpcSender;
 use msg::constellation_msg::PipelineId;
 use profile_traits::time::{ProfilerChan, ProfilerCategory, send_profile_data};
 use profile_traits::time::TimerMetadata;
-use script_traits::{ConstellationControlMsg, LayoutMsg, PaintMetricType};
+use script_traits::{ConstellationControlMsg, LayoutMsg, ProgressiveWebMetricType};
 use servo_config::opts;
 use std::cell::{Cell, RefCell};
+use std::cmp::Ordering;
 use std::collections::HashMap;
+use time::precise_time_ns;
 
 pub trait ProfilerMetadataFactory {
     fn new_metadata(&self) -> Option<TimerMetadata>;
 }
 
-macro_rules! make_time_setter(
+pub trait ProgressiveWebMetric {
-    ( $attr:ident, $func:ident, $category:ident, $label:expr, $metric_type:path ) => (
+    fn get_navigation_start(&self) -> Option<f64>;
-        fn $func(&self,
+    fn set_navigation_start(&mut self, time: f64);
-                 profiler_metadata: Option<TimerMetadata>,
+    fn get_time_profiler_chan(&self) -> &ProfilerChan;
-                 paint_time: f64) {
+    fn send_queued_constellation_msg(&self, name: ProgressiveWebMetricType, time: f64);
-            if self.$attr.get().is_some() {
-                return;
 }
 
-            let navigation_start = match self.navigation_start {
+/// maximum task time is 50ms (in ns)
+pub const MAX_TASK_NS: u64 = 50000000;
+/// 10 second window (in ns)
+const INTERACTIVE_WINDOW_SECONDS_IN_NS: u64 = 10000000000;
+
+
+fn set_metric<U: ProgressiveWebMetric>(
+    pwm: &U,
+    metadata: Option<TimerMetadata>,
+    metric_type: ProgressiveWebMetricType,
+    category: ProfilerCategory,
+    attr: &Cell<Option<f64>>,
+    metric_time: Option<f64>)
+{
+    let navigation_start = match pwm.get_navigation_start() {
         Some(time) => time,
         None => {
             warn!("Trying to set metric before navigation start");
             return;
         }
     };
-
+    let now = match metric_time {
-            let time = paint_time - navigation_start;
+        Some(time) => time,
-            self.$attr.set(Some(time));
+        None => precise_time_ns() as f64,
+    };
+    let time = now - navigation_start;
+    attr.set(Some(time));
 
     // Queue performance observer notification.
-            let msg = ConstellationControlMsg::PaintMetric(self.pipeline_id,
+    pwm.send_queued_constellation_msg(metric_type, time);
-                                                           $metric_type,
-                                                           time);
-            if let Err(e) = self.script_chan.send(msg) {
-                warn!("Sending paint metric to script thread failed ({}).", e);
-            }
 
     // Send the metric to the time profiler.
-            send_profile_data(ProfilerCategory::$category,
+    send_profile_data(
-                              profiler_metadata,
+        category,
-                              &self.time_profiler_chan,
+        metadata,
-                              time as u64, time as u64, 0, 0);
+        &pwm.get_time_profiler_chan(),
+        time as u64,
+        time as u64,
+        0,
+        0,
+    );
 
     // Print the metric to console if the print-pwm option was given.
     if opts::get().print_pwm {
-                println!("{:?} {:?}", $label, time);
+        println!("{:?} {:?}", metric_type, time);
+    }
+
+}
+
+// https://github.com/GoogleChrome/lighthouse/issues/27
+// we can look at three different metrics here:
+// navigation start -> visually ready (dom content loaded)
+// navigation start -> thread ready (main thread available)
+// visually ready -> thread ready
+#[derive(MallocSizeOf)]
+pub struct InteractiveMetrics {
+    /// when we navigated to the page
+    navigation_start: Option<f64>,
+    /// indicates if the page is visually ready
+    dom_content_loaded: Cell<Option<f64>>,
+    /// main thread is available -- there's been a 10s window with no tasks longer than 50ms
+    main_thread_available: Cell<Option<f64>>,
+    // max(main_thread_available, dom_content_loaded)
+    time_to_interactive: Cell<Option<f64>>,
+    #[ignore_malloc_size_of = "can't measure channels"]
+    time_profiler_chan: ProfilerChan,
+}
+
+#[derive(Clone, Copy, Debug, MallocSizeOf)]
+pub struct InteractiveWindow {
+    start: u64,
+}
+
+
+impl InteractiveWindow {
+    pub fn new() -> InteractiveWindow {
+        InteractiveWindow {
+            start: precise_time_ns(),
+        }
+    }
+
+    // We need to either start or restart the 10s window
+    //   start: we've added a new document
+    //   restart: there was a task > 50ms
+    //   not all documents are interactive
+    pub fn start_window(&mut self) {
+        self.start = precise_time_ns();
+    }
+
+    /// check if 10s has elapsed since start
+    pub fn needs_check(&self) -> bool {
+        precise_time_ns() - self.start >= INTERACTIVE_WINDOW_SECONDS_IN_NS
+    }
+
+    pub fn get_start(&self) -> u64 {
+        self.start
+    }
+}
+
+#[derive(Debug)]
+pub enum InteractiveFlag {
+    DOMContentLoaded,
+    TimeToInteractive(f64),
+}
+
+impl InteractiveMetrics {
+    pub fn new(time_profiler_chan: ProfilerChan) -> InteractiveMetrics {
+        InteractiveMetrics {
+            navigation_start: None,
+            dom_content_loaded: Cell::new(None),
+            main_thread_available: Cell::new(None),
+            time_to_interactive: Cell::new(None),
+            time_profiler_chan: time_profiler_chan,
+        }
+    }
+
+    pub fn set_dom_content_loaded(&self) {
+        if self.dom_content_loaded.get().is_none() {
+            self.dom_content_loaded.set(Some(precise_time_ns() as f64));
+        }
+    }
+
+    pub fn set_main_thread_available(&self, time: f64) {
+        if self.main_thread_available.get().is_none() {
+            self.main_thread_available.set(Some(time));
+        }
+    }
+
+    pub fn get_dom_content_loaded(&self) -> Option<f64> {
+        self.dom_content_loaded.get()
+    }
+
+    pub fn get_main_thread_available(&self) -> Option<f64> {
+        self.main_thread_available.get()
+    }
+
+    // can set either dlc or tti first, but both must be set to actually calc metric
+    // when the second is set, set_tti is called with appropriate time
+    pub fn maybe_set_tti<T>(
+        &self,
+        profiler_metadata_factory: &T,
+        metric: InteractiveFlag,
+    ) where
+        T: ProfilerMetadataFactory,
+    {
+        if self.get_tti().is_some() {
+            return;
+        }
+        match metric {
+            InteractiveFlag::DOMContentLoaded => self.set_dom_content_loaded(),
+            InteractiveFlag::TimeToInteractive(time) => self.set_main_thread_available(time),
+        }
+
+        let dcl = self.dom_content_loaded.get();
+        let mta = self.main_thread_available.get();
+        let (dcl, mta) = match (dcl, mta) {
+        (Some(dcl), Some(mta)) => (dcl, mta),
+            _ => return,
+        };
+        let metric_time = match dcl.partial_cmp(&mta) {
+            Some(Ordering::Less) => mta,
+            Some(_) => dcl,
+            None => panic!("no ordering possible. something bad happened"),
+        };
+        set_metric(
+            self,
+            profiler_metadata_factory.new_metadata(),
+            ProgressiveWebMetricType::TimeToInteractive,
+            ProfilerCategory::TimeToInteractive,
+            &self.time_to_interactive,
+            Some(metric_time));
+    }
+
+    pub fn get_tti(&self) -> Option<f64> {
+        self.time_to_interactive.get()
+    }
+}
+
+impl ProgressiveWebMetric for InteractiveMetrics {
+    fn get_navigation_start(&self) -> Option<f64> {
+        self.navigation_start
+    }
+
+    fn set_navigation_start(&mut self, time: f64) {
+        self.navigation_start = Some(time);
+    }
+
+    fn send_queued_constellation_msg(&self, name: ProgressiveWebMetricType, time: f64) { }
+
+    fn get_time_profiler_chan(&self) -> &ProfilerChan {
+        &self.time_profiler_chan
     }
 }
-    );
-);
 
 pub struct PaintTimeMetrics {
     pending_metrics: RefCell<HashMap<Epoch, (Option<TimerMetadata>, bool)>>,
@@ -81,7 +246,8 @@ pub struct PaintTimeMetrics {
 }
 
 impl PaintTimeMetrics {
-    pub fn new(pipeline_id: PipelineId,
+    pub fn new(
+        pipeline_id: PipelineId,
         time_profiler_chan: ProfilerChan,
         constellation_chan: IpcSender<LayoutMsg>,
         script_chan: IpcSender<ConstellationControlMsg>)
@@ -98,20 +264,26 @@ impl PaintTimeMetrics {
         }
     }
 
-    pub fn set_navigation_start(&mut self, time: f64) {
+    pub fn maybe_set_first_paint<T>(&self, profiler_metadata_factory: &T)
-        self.navigation_start = Some(time);
+    where
+        T: ProfilerMetadataFactory,
+    {
+        if self.first_paint.get().is_some() {
+            return;
         }
 
-    make_time_setter!(first_paint, set_first_paint,
+        set_metric(
-                      TimeToFirstPaint,
+            self,
-                      "first-paint",
+            profiler_metadata_factory.new_metadata(),
-                      PaintMetricType::FirstPaint);
+            ProgressiveWebMetricType::FirstPaint,
-    make_time_setter!(first_contentful_paint, set_first_contentful_paint,
+            ProfilerCategory::TimeToFirstPaint,
-                      TimeToFirstContentfulPaint,
+            &self.first_paint,
-                      "first-contentful-paint",
+            None,
-                      PaintMetricType::FirstContentfulPaint);
+        );
+    }
 
-    pub fn maybe_observe_paint_time<T>(&self,
+    pub fn maybe_observe_paint_time<T>(
+        &self,
         profiler_metadata_factory: &T,
         epoch: Epoch,
         display_list: &DisplayList)
@@ -131,15 +303,15 @@ impl PaintTimeMetrics {
                 &DisplayItem::Image(_) => {
                     is_contentful = true;
                     break;
-                },
+                }
                 _ => (),
             }
         }
 
-        self.pending_metrics.borrow_mut().insert(
+        self.pending_metrics.borrow_mut().insert(epoch, (
-            epoch,
+            profiler_metadata_factory.new_metadata(),
-            (profiler_metadata_factory.new_metadata(), is_contentful)
+            is_contentful,
-        );
+        ));
 
         // Send the pending metric information to the compositor thread.
         // The compositor will record the current time after painting the
@@ -150,8 +322,8 @@ impl PaintTimeMetrics {
         }
     }
 
-    pub fn maybe_set_metric(&mut self, epoch: Epoch, paint_time: f64) {
+    pub fn maybe_set_metric(&self, epoch: Epoch, paint_time: f64) {
-        if (self.first_paint.get().is_some() && self.first_contentful_paint.get().is_some()) ||
+        if self.first_paint.get().is_some() && self.first_contentful_paint.get().is_some() ||
             self.navigation_start.is_none() {
             // If we already set all paint metrics or we have not set navigation start yet,
             // we just bail out.
@@ -160,16 +332,26 @@ impl PaintTimeMetrics {
 
         if let Some(pending_metric) = self.pending_metrics.borrow_mut().remove(&epoch) {
             let profiler_metadata = pending_metric.0;
-            self.set_first_paint(profiler_metadata.clone(), paint_time);
+            set_metric(
+                self,
+                profiler_metadata.clone(),
+                ProgressiveWebMetricType::FirstPaint,
+                ProfilerCategory::TimeToFirstPaint,
+                &self.first_paint,
+                Some(paint_time),
+            );
+
             if pending_metric.1 {
-                self.set_first_contentful_paint(profiler_metadata, paint_time);
+                set_metric(
+                    self,
+                    profiler_metadata,
+                    ProgressiveWebMetricType::FirstContentfulPaint,
+                    ProfilerCategory::TimeToFirstContentfulPaint,
+                    &self.first_contentful_paint,
+                    Some(paint_time),
+                );
             }
         }
-
-    }
-
-    pub fn get_navigation_start(&self) -> Option<f64> {
-        self.navigation_start
     }
 
     pub fn get_first_paint(&self) -> Option<f64> {
@@ -180,3 +362,24 @@ impl PaintTimeMetrics {
         self.first_contentful_paint.get()
     }
 }
+
+impl ProgressiveWebMetric for PaintTimeMetrics {
+    fn get_navigation_start(&self) -> Option<f64> {
+        self.navigation_start
+    }
+
+    fn set_navigation_start(&mut self, time: f64) {
+        self.navigation_start = Some(time);
+    }
+
+    fn send_queued_constellation_msg(&self, name: ProgressiveWebMetricType, time: f64) {
+        let msg = ConstellationControlMsg::PaintMetric(self.pipeline_id, name, time);
+        if let Err(e) = self.script_chan.send(msg) {
+            warn!("Sending metric to script thread failed ({}).", e);
+        }
+    }
+
+    fn get_time_profiler_chan(&self) -> &ProfilerChan {
+        &self.time_profiler_chan
+    }
+}

components/profile/time.rs

@@ -157,6 +157,7 @@ impl Formattable for ProfilerCategory {
             ProfilerCategory::ScriptPerformanceEvent => "Script Performance Event",
             ProfilerCategory::TimeToFirstPaint => "Time To First Paint",
             ProfilerCategory::TimeToFirstContentfulPaint => "Time To First Contentful Paint",
+            ProfilerCategory::TimeToInteractive => "Time to Interactive",
             ProfilerCategory::ApplicationHeartbeat => "Application Heartbeat",
         };
         format!("{}{}", padding, name)

components/profile_traits/time.rs

@@ -93,6 +93,7 @@ pub enum ProfilerCategory {
     ScriptPerformanceEvent = 0x7b,
     TimeToFirstPaint = 0x80,
     TimeToFirstContentfulPaint = 0x81,
+    TimeToInteractive = 0x82,
     ApplicationHeartbeat = 0x90,
 }
 
@@ -113,7 +114,7 @@ pub fn profile<T, F>(category: ProfilerCategory,
                      profiler_chan: ProfilerChan,
                      callback: F)
                   -> T
-    where F: FnOnce() -> T
+    where F: FnOnce() -> T,
 {
     if opts::get().signpost {
         signpost::start(category as u32, &[0, 0, 0, (category as usize) >> 4]);

components/script/dom/bindings/trace.rs

@@ -61,6 +61,7 @@ use js::glue::{CallObjectTracer, CallValueTracer};
 use js::jsapi::{GCTraceKindToAscii, Heap, JSObject, JSTracer, TraceKind};
 use js::jsval::JSVal;
 use js::rust::Runtime;
+use metrics::{InteractiveMetrics, InteractiveWindow};
 use msg::constellation_msg::{BrowsingContextId, FrameType, PipelineId, TopLevelBrowsingContextId};
 use net_traits::{Metadata, NetworkError, ReferrerPolicy, ResourceThreads};
 use net_traits::filemanager_thread::RelativePos;
@@ -283,7 +284,7 @@ unsafe impl<T: JSTraceable, U: JSTraceable> JSTraceable for Result<T, U> {
 unsafe impl<K, V, S> JSTraceable for HashMap<K, V, S>
     where K: Hash + Eq + JSTraceable,
           V: JSTraceable,
-          S: BuildHasher
+          S: BuildHasher,
 {
     #[inline]
     unsafe fn trace(&self, trc: *mut JSTracer) {
@@ -296,7 +297,7 @@ unsafe impl<K, V, S> JSTraceable for HashMap<K, V, S>
 
 unsafe impl<T, S> JSTraceable for HashSet<T, S>
     where T: Hash + Eq + JSTraceable,
-          S: BuildHasher
+          S: BuildHasher,
 {
     #[inline]
     unsafe fn trace(&self, trc: *mut JSTracer) {
@@ -413,6 +414,8 @@ unsafe_no_jsmanaged_fields!(WebGLVertexArrayId);
 unsafe_no_jsmanaged_fields!(MediaList);
 unsafe_no_jsmanaged_fields!(WebVRGamepadHand);
 unsafe_no_jsmanaged_fields!(ScriptToConstellationChan);
+unsafe_no_jsmanaged_fields!(InteractiveMetrics);
+unsafe_no_jsmanaged_fields!(InteractiveWindow);
 
 unsafe impl<'a> JSTraceable for &'a str {
     #[inline]

components/script/dom/dedicatedworkerglobalscope.rs

@@ -195,7 +195,8 @@ impl DedicatedWorkerGlobalScope {
                     println!("error loading script {}", serialized_worker_url);
                     parent_sender.send(CommonScriptMsg::Task(
                         WorkerEvent,
-                        Box::new(SimpleWorkerErrorHandler::new(worker))
+                        Box::new(SimpleWorkerErrorHandler::new(worker)),
+                        pipeline_id
                     )).unwrap();
                     return;
                 }
@@ -357,6 +358,7 @@ impl DedicatedWorkerGlobalScope {
     #[allow(unsafe_code)]
     pub fn forward_error_to_worker_object(&self, error_info: ErrorInfo) {
         let worker = self.worker.borrow().as_ref().unwrap().clone();
+        let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
         let task = Box::new(task!(forward_error_to_worker_object: move || {
             let worker = worker.root();
             let global = worker.global();
@@ -382,7 +384,7 @@ impl DedicatedWorkerGlobalScope {
             }
         }));
         // TODO: Should use the DOM manipulation task source.
-        self.parent_sender.send(CommonScriptMsg::Task(WorkerEvent, task)).unwrap();
+        self.parent_sender.send(CommonScriptMsg::Task(WorkerEvent, task, Some(pipeline_id))).unwrap();
     }
 }
 
@@ -403,10 +405,11 @@ impl DedicatedWorkerGlobalScopeMethods for DedicatedWorkerGlobalScope {
     unsafe fn PostMessage(&self, cx: *mut JSContext, message: HandleValue) -> ErrorResult {
         let data = StructuredCloneData::write(cx, message)?;
         let worker = self.worker.borrow().as_ref().unwrap().clone();
+        let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
         let task = Box::new(task!(post_worker_message: move || {
             Worker::handle_message(worker, data);
         }));
-        self.parent_sender.send(CommonScriptMsg::Task(WorkerEvent, task)).unwrap();
+        self.parent_sender.send(CommonScriptMsg::Task(WorkerEvent, task, Some(pipeline_id))).unwrap();
         Ok(())
     }
 

components/script/dom/document.rs

@@ -99,6 +99,7 @@ use hyper_serde::Serde;
 use ipc_channel::ipc::{self, IpcSender};
 use js::jsapi::{JSContext, JSRuntime};
 use js::jsapi::JS_GetRuntime;
+use metrics::{InteractiveFlag, InteractiveMetrics, InteractiveWindow, ProfilerMetadataFactory};
 use msg::constellation_msg::{ALT, CONTROL, SHIFT, SUPER};
 use msg::constellation_msg::{BrowsingContextId, Key, KeyModifiers, KeyState, TopLevelBrowsingContextId};
 use net_traits::{FetchResponseMsg, IpcSend, ReferrerPolicy};
@@ -108,6 +109,7 @@ use net_traits::pub_domains::is_pub_domain;
 use net_traits::request::RequestInit;
 use net_traits::response::HttpsState;
 use num_traits::ToPrimitive;
+use profile_traits::time::{TimerMetadata, TimerMetadataFrameType, TimerMetadataReflowType};
 use script_layout_interface::message::{Msg, NodesFromPointQueryType, ReflowGoal};
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::{MainThreadScriptMsg, ScriptThread};
@@ -360,6 +362,8 @@ pub struct Document {
     /// is inserted or removed from the document.
     /// See https://html.spec.whatwg.org/multipage/#form-owner
     form_id_listener_map: DomRefCell<HashMap<Atom, HashSet<Dom<Element>>>>,
+    interactive_time: DomRefCell<InteractiveMetrics>,
+    tti_window: DomRefCell<InteractiveWindow>,
 }
 
 #[derive(JSTraceable, MallocSizeOf)]
@@ -1834,6 +1838,9 @@ impl Document {
         window.reflow(ReflowGoal::Full, ReflowReason::DOMContentLoaded);
         update_with_current_time_ms(&self.dom_content_loaded_event_end);
 
+        // html parsing has finished - set dom content loaded
+        self.interactive_time.borrow().maybe_set_tti(self, InteractiveFlag::DOMContentLoaded);
+
         // Step 4.2.
         // TODO: client message queue.
     }
@@ -1916,6 +1923,14 @@ impl Document {
         self.dom_interactive.get()
     }
 
+    pub fn get_interactive_metrics(&self) -> Ref<InteractiveMetrics> {
+        self.interactive_time.borrow()
+    }
+
+    pub fn has_recorded_tti_metric(&self) -> bool {
+        self.get_interactive_metrics().get_tti().is_some()
+    }
+
     pub fn get_dom_content_loaded_event_start(&self) -> u64 {
         self.dom_content_loaded_event_start.get()
     }
@@ -1936,6 +1951,22 @@ impl Document {
         self.load_event_end.get()
     }
 
+    pub fn start_tti(&self) {
+        self.tti_window.borrow_mut().start_window();
+    }
+
+    /// check tti for this document
+    /// if it's been 10s since this doc encountered a task over 50ms, then we consider the
+    /// main thread available and try to set tti
+    pub fn record_tti_if_necessary(&self) {
+        if self.has_recorded_tti_metric() { return; }
+
+        if self.tti_window.borrow().needs_check() {
+            self.get_interactive_metrics().maybe_set_tti(self,
+                InteractiveFlag::TimeToInteractive(self.tti_window.borrow().get_start() as f64));
+        }
+    }
+
     // https://html.spec.whatwg.org/multipage/#fire-a-focus-event
     fn fire_focus_event(&self, focus_event_type: FocusEventType, node: &Node, related_target: Option<&EventTarget>) {
         let (event_name, does_bubble) = match focus_event_type {
@@ -2145,6 +2176,8 @@ impl Document {
             (DocumentReadyState::Complete, true)
         };
 
+        let interactive_time = InteractiveMetrics::new(window.time_profiler_chan().clone());
+
         Document {
             node: Node::new_document_node(),
             window: Dom::from_ref(window),
@@ -2236,6 +2269,8 @@ impl Document {
             dom_count: Cell::new(1),
             fullscreen_element: MutNullableDom::new(None),
             form_id_listener_map: Default::default(),
+            interactive_time: DomRefCell::new(interactive_time),
+            tti_window: DomRefCell::new(InteractiveWindow::new()),
         }
     }
 
@@ -2579,11 +2614,13 @@ impl Document {
             self.send_to_constellation(event);
         }
 
+        let pipeline_id = self.window().pipeline_id();
+
         // Step 7
         let trusted_pending = Trusted::new(pending);
         let trusted_promise = TrustedPromise::new(promise.clone());
         let handler = ElementPerformFullscreenEnter::new(trusted_pending, trusted_promise, error);
-        let script_msg = CommonScriptMsg::Task(ScriptThreadEventCategory::EnterFullscreen, handler);
+        let script_msg = CommonScriptMsg::Task(ScriptThreadEventCategory::EnterFullscreen, handler, pipeline_id);
         let msg = MainThreadScriptMsg::Common(script_msg);
         window.main_thread_script_chan().send(msg).unwrap();
 
@@ -2615,7 +2652,8 @@ impl Document {
         let trusted_element = Trusted::new(element.r());
         let trusted_promise = TrustedPromise::new(promise.clone());
         let handler = ElementPerformFullscreenExit::new(trusted_element, trusted_promise);
-        let script_msg = CommonScriptMsg::Task(ScriptThreadEventCategory::ExitFullscreen, handler);
+        let pipeline_id = Some(global.pipeline_id());
+        let script_msg = CommonScriptMsg::Task(ScriptThreadEventCategory::ExitFullscreen, handler, pipeline_id);
         let msg = MainThreadScriptMsg::Common(script_msg);
         window.main_thread_script_chan().send(msg).unwrap();
 
@@ -2673,6 +2711,16 @@ impl Element {
     }
 }
 
+impl ProfilerMetadataFactory for Document {
+    fn new_metadata(&self) -> Option<TimerMetadata> {
+        Some(TimerMetadata {
+            url: String::from(self.url().as_str()),
+            iframe: TimerMetadataFrameType::RootWindow,
+            incremental: TimerMetadataReflowType::Incremental,
+        })
+    }
+}
+
 impl DocumentMethods for Document {
     // https://drafts.csswg.org/cssom/#dom-document-stylesheets
     fn StyleSheets(&self) -> DomRoot<StyleSheetList> {

components/script/dom/performancepainttiming.rs

@@ -9,7 +9,7 @@ use dom::bindings::str::DOMString;
 use dom::globalscope::GlobalScope;
 use dom::performanceentry::PerformanceEntry;
 use dom_struct::dom_struct;
-use script_traits::PaintMetricType;
+use script_traits::ProgressiveWebMetricType;
 
 #[dom_struct]
 pub struct PerformancePaintTiming {
@@ -17,11 +17,11 @@ pub struct PerformancePaintTiming {
 }
 
 impl PerformancePaintTiming {
-    fn new_inherited(metric_type: PaintMetricType, start_time: f64)
+    fn new_inherited(metric_type: ProgressiveWebMetricType, start_time: f64) -> PerformancePaintTiming {
-        -> PerformancePaintTiming {
         let name = match metric_type {
-            PaintMetricType::FirstPaint => DOMString::from("first-paint"),
+            ProgressiveWebMetricType::FirstPaint => DOMString::from("first-paint"),
-            PaintMetricType::FirstContentfulPaint => DOMString::from("first-contentful-paint"),
+            ProgressiveWebMetricType::FirstContentfulPaint => DOMString::from("first-contentful-paint"),
+            _ => DOMString::from(""),
         };
         PerformancePaintTiming {
             entry: PerformanceEntry::new_inherited(name,
@@ -33,7 +33,7 @@ impl PerformancePaintTiming {
 
     #[allow(unrooted_must_root)]
     pub fn new(global: &GlobalScope,
-               metric_type: PaintMetricType,
+               metric_type: ProgressiveWebMetricType,
                start_time: f64) -> DomRoot<PerformancePaintTiming> {
         let entry = PerformancePaintTiming::new_inherited(metric_type, start_time);
         reflect_dom_object(Box::new(entry), global, PerformancePaintTimingBinding::Wrap)

components/script/dom/vrdisplay.rs

@@ -494,6 +494,7 @@ impl VRDisplay {
         let address = Trusted::new(&*self);
         let near_init = self.depth_near.get();
         let far_init = self.depth_far.get();
+        let pipeline_id = self.global().pipeline_id();
 
         // The render loop at native headset frame rate is implemented using a dedicated thread.
         // Every loop iteration syncs pose data with the HMD, submits the pixels to the display and waits for Vsync.
@@ -515,7 +516,7 @@ impl VRDisplay {
                 let task = Box::new(task!(handle_vrdisplay_raf: move || {
                     this.root().handle_raf(&sender);
                 }));
-                js_sender.send(CommonScriptMsg::Task(WebVREvent, task)).unwrap();
+                js_sender.send(CommonScriptMsg::Task(WebVREvent, task, Some(pipeline_id))).unwrap();
 
                 // Run Sync Poses in parallell on Render thread
                 let msg = WebVRCommand::SyncPoses(display_id, near, far, sync_sender.clone());

components/script/dom/websocket.rs

@@ -262,9 +262,10 @@ impl WebSocket {
                 address: address,
             });
 
+            let pipeline_id = self.global().pipeline_id();
             self.global()
                 .script_chan()
-                .send(CommonScriptMsg::Task(WebSocketEvent, task))
+                .send(CommonScriptMsg::Task(WebSocketEvent, task, Some(pipeline_id)))
                 .unwrap();
         }
 

components/script/dom/window.rs

@@ -304,6 +304,11 @@ impl Window {
         }
     }
 
+    /// Get a sender to the time profiler thread.
+    pub fn time_profiler_chan(&self) -> &TimeProfilerChan {
+        self.globalscope.time_profiler_chan()
+    }
+
     pub fn origin(&self) -> &MutableOrigin {
         self.globalscope.origin()
     }
@@ -1040,6 +1045,10 @@ impl Window {
         }
     }
 
+    pub fn get_navigation_start(&self) -> f64 {
+        self.navigation_start_precise.get()
+    }
+
     /// Cancels all the tasks associated with that window.
     ///
     /// This sets the current `ignore_further_async_events` sentinel value to
@@ -1854,6 +1863,10 @@ impl Window {
             WindowBinding::Wrap(runtime.cx(), win)
         }
     }
+
+    pub fn pipeline_id(&self) -> Option<PipelineId> {
+        Some(self.upcast::<GlobalScope>().pipeline_id())
+    }
 }
 
 fn should_move_clip_rect(clip_rect: Rect<Au>, new_viewport: Rect<f32>) -> bool {
@@ -1962,6 +1975,7 @@ impl Window {
         let _ = self.script_chan.send(CommonScriptMsg::Task(
             ScriptThreadEventCategory::DomEvent,
             Box::new(self.task_canceller().wrap_task(task)),
+            self.pipeline_id()
         ));
     }
 }

components/script/dom/workerglobalscope.rs

@@ -29,6 +29,7 @@ use ipc_channel::ipc::IpcSender;
 use js::jsapi::{HandleValue, JSAutoCompartment, JSContext, JSRuntime};
 use js::jsval::UndefinedValue;
 use js::panic::maybe_resume_unwind;
+use msg::constellation_msg::PipelineId;
 use net_traits::{IpcSend, load_whole_resource};
 use net_traits::request::{CredentialsMode, Destination, RequestInit as NetRequestInit};
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, get_reports, Runtime};
@@ -165,6 +166,10 @@ impl WorkerGlobalScope {
             cancelled: self.closing.clone(),
         }
     }
+
+    pub fn pipeline_id(&self) -> PipelineId {
+        self.globalscope.pipeline_id()
+    }
 }
 
 impl WorkerGlobalScopeMethods for WorkerGlobalScope {
@@ -363,15 +368,15 @@ impl WorkerGlobalScope {
     }
 
     pub fn file_reading_task_source(&self) -> FileReadingTaskSource {
-        FileReadingTaskSource(self.script_chan())
+        FileReadingTaskSource(self.script_chan(), self.pipeline_id())
     }
 
     pub fn networking_task_source(&self) -> NetworkingTaskSource {
-        NetworkingTaskSource(self.script_chan())
+        NetworkingTaskSource(self.script_chan(), self.pipeline_id())
     }
 
     pub fn performance_timeline_task_source(&self) -> PerformanceTimelineTaskSource {
-        PerformanceTimelineTaskSource(self.script_chan())
+        PerformanceTimelineTaskSource(self.script_chan(), self.pipeline_id())
     }
 
     pub fn new_script_pair(&self) -> (Box<ScriptChan + Send>, Box<ScriptPort + Send>) {
@@ -385,7 +390,7 @@ impl WorkerGlobalScope {
 
     pub fn process_event(&self, msg: CommonScriptMsg) {
         match msg {
-            CommonScriptMsg::Task(_, task) => {
+            CommonScriptMsg::Task(_, task, _) => {
                 task.run_box()
             },
             CommonScriptMsg::CollectReports(reports_chan) => {

components/script/dom/worklet.rs

@@ -644,7 +644,7 @@ impl WorkletThread {
     where
         T: TaskBox + 'static,
     {
-        let msg = CommonScriptMsg::Task(ScriptThreadEventCategory::WorkletEvent, Box::new(task));
+        let msg = CommonScriptMsg::Task(ScriptThreadEventCategory::WorkletEvent, Box::new(task), None);
         let msg = MainThreadScriptMsg::Common(msg);
         self.global_init.to_script_thread_sender.send(msg).expect("Worklet thread outlived script thread.");
     }

components/script/dom/xmlhttprequest.rs

@@ -1286,7 +1286,7 @@ impl XMLHttpRequest {
 
         let (task_source, script_port) = if self.sync.get() {
             let (tx, rx) = global.new_script_pair();
-            (NetworkingTaskSource(tx), Some(rx))
+            (NetworkingTaskSource(tx, global.pipeline_id()), Some(rx))
         } else {
             (global.networking_task_source(), None)
         };

components/script/script_runtime.rs

@@ -22,6 +22,7 @@ use js::jsapi::{JSObject, RuntimeOptionsRef, SetPreserveWrapperCallback, SetEnqu
 use js::panic::wrap_panic;
 use js::rust::Runtime as RustRuntime;
 use microtask::{EnqueuedPromiseCallback, Microtask};
+use msg::constellation_msg::PipelineId;
 use profile_traits::mem::{Report, ReportKind, ReportsChan};
 use script_thread::trace_thread;
 use servo_config::opts;
@@ -44,14 +45,14 @@ pub enum CommonScriptMsg {
     /// supplied channel.
     CollectReports(ReportsChan),
     /// Generic message that encapsulates event handling.
-    Task(ScriptThreadEventCategory, Box<TaskBox>),
+    Task(ScriptThreadEventCategory, Box<TaskBox>, Option<PipelineId>),
 }
 
 impl fmt::Debug for CommonScriptMsg {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             CommonScriptMsg::CollectReports(_) => write!(f, "CollectReports(...)"),
-            CommonScriptMsg::Task(ref category, ref task) => {
+            CommonScriptMsg::Task(ref category, ref task, _) => {
                 f.debug_tuple("Task").field(category).field(task).finish()
             },
         }

components/script/script_thread.rs

@@ -74,7 +74,7 @@ use js::jsapi::{JSTracer, SetWindowProxyClass};
 use js::jsval::UndefinedValue;
 use malloc_size_of::MallocSizeOfOps;
 use mem::malloc_size_of_including_self;
-use metrics::PaintTimeMetrics;
+use metrics::{MAX_TASK_NS, PaintTimeMetrics};
 use microtask::{MicrotaskQueue, Microtask};
 use msg::constellation_msg::{BrowsingContextId, FrameType, PipelineId, PipelineNamespace, TopLevelBrowsingContextId};
 use net_traits::{FetchMetadata, FetchResponseListener, FetchResponseMsg};
@@ -91,7 +91,7 @@ use script_traits::{CompositorEvent, ConstellationControlMsg};
 use script_traits::{DiscardBrowsingContext, DocumentActivity, EventResult};
 use script_traits::{InitialScriptState, JsEvalResult, LayoutMsg, LoadData};
 use script_traits::{MouseButton, MouseEventType, MozBrowserEvent, NewLayoutInfo};
-use script_traits::{PaintMetricType, Painter, ScriptMsg, ScriptThreadFactory};
+use script_traits::{ProgressiveWebMetricType, Painter, ScriptMsg, ScriptThreadFactory};
 use script_traits::{ScriptToConstellationChan, TimerEvent, TimerSchedulerMsg};
 use script_traits::{TimerSource, TouchEventType, TouchId, UntrustedNodeAddress};
 use script_traits::{UpdatePipelineIdReason, WindowSizeData, WindowSizeType};
@@ -345,6 +345,10 @@ impl Documents {
         self.map.get(&pipeline_id).map(|doc| DomRoot::from_ref(&**doc))
     }
 
+    pub fn len(&self) -> usize {
+        self.map.len()
+    }
+
     pub fn find_window(&self, pipeline_id: PipelineId) -> Option<DomRoot<Window>> {
         self.find_document(pipeline_id).map(|doc| DomRoot::from_ref(doc.window()))
     }
@@ -410,17 +414,17 @@ pub struct ScriptThread {
     /// events in the event queue.
     chan: MainThreadScriptChan,
 
-    dom_manipulation_task_source: DOMManipulationTaskSource,
+    dom_manipulation_task_sender: Sender<MainThreadScriptMsg>,
 
-    user_interaction_task_source: UserInteractionTaskSource,
+    user_interaction_task_sender: Sender<MainThreadScriptMsg>,
 
-    networking_task_source: NetworkingTaskSource,
+    networking_task_sender: Box<ScriptChan>,
 
     history_traversal_task_source: HistoryTraversalTaskSource,
 
-    file_reading_task_source: FileReadingTaskSource,
+    file_reading_task_sender: Box<ScriptChan>,
 
-    performance_timeline_task_source: PerformanceTimelineTaskSource,
+    performance_timeline_task_sender: Box<ScriptChan>,
 
     /// A channel to hand out to threads that need to respond to a message from the script thread.
     control_chan: IpcSender<ConstellationControlMsg>,
@@ -681,7 +685,8 @@ impl ScriptThread {
         SCRIPT_THREAD_ROOT.with(|root| {
             if let Some(script_thread) = root.get() {
                 let script_thread = unsafe { &*script_thread };
-                script_thread.profile_event(ScriptThreadEventCategory::AttachLayout, || {
+                let pipeline_id = Some(new_layout_info.new_pipeline_id);
+                script_thread.profile_event(ScriptThreadEventCategory::AttachLayout, pipeline_id, || {
                     script_thread.handle_new_layout(new_layout_info, origin);
                 })
             }
@@ -727,8 +732,8 @@ impl ScriptThread {
         pipeline_id: PipelineId,
         name: Atom,
         properties: Vec<Atom>,
-        painter: Box<Painter>,
+        painter: Box<Painter>)
-    ) {
+    {
         let window = self.documents.borrow().find_window(pipeline_id);
         let window = match window {
             Some(window) => window,
@@ -830,17 +835,18 @@ impl ScriptThread {
             port: port,
 
             chan: MainThreadScriptChan(chan.clone()),
-            dom_manipulation_task_source: DOMManipulationTaskSource(chan.clone()),
+            dom_manipulation_task_sender: chan.clone(),
-            user_interaction_task_source: UserInteractionTaskSource(chan.clone()),
+            user_interaction_task_sender: chan.clone(),
-            networking_task_source: NetworkingTaskSource(boxed_script_sender.clone()),
+            networking_task_sender: boxed_script_sender.clone(),
+            file_reading_task_sender: boxed_script_sender.clone(),
+            performance_timeline_task_sender: boxed_script_sender.clone(),
+
             history_traversal_task_source: HistoryTraversalTaskSource(chan),
-            file_reading_task_source: FileReadingTaskSource(boxed_script_sender.clone()),
-            performance_timeline_task_source: PerformanceTimelineTaskSource(boxed_script_sender),
 
             control_chan: state.control_chan,
             control_port: control_port,
             script_sender: state.script_to_constellation_chan.sender.clone(),
-            time_profiler_chan: state.time_profiler_chan,
+            time_profiler_chan: state.time_profiler_chan.clone(),
             mem_profiler_chan: state.mem_profiler_chan,
 
             devtools_chan: state.devtools_chan,
@@ -964,7 +970,8 @@ impl ScriptThread {
                 // child list yet, causing the find() to fail.
                 FromConstellation(ConstellationControlMsg::AttachLayout(
                         new_layout_info)) => {
-                    self.profile_event(ScriptThreadEventCategory::AttachLayout, || {
+                    let pipeline_id = new_layout_info.new_pipeline_id;
+                    self.profile_event(ScriptThreadEventCategory::AttachLayout, Some(pipeline_id), || {
                         // If this is an about:blank load, it must share the creator's origin.
                         // This must match the logic in the constellation when creating a new pipeline
                         let origin = if new_layout_info.load_data.url.as_str() != "about:blank" {
@@ -986,17 +993,17 @@ impl ScriptThread {
                 }
                 FromConstellation(ConstellationControlMsg::Resize(id, size, size_type)) => {
                     // step 7.7
-                    self.profile_event(ScriptThreadEventCategory::Resize, || {
+                    self.profile_event(ScriptThreadEventCategory::Resize, Some(id), || {
                         self.handle_resize(id, size, size_type);
                     })
                 }
                 FromConstellation(ConstellationControlMsg::Viewport(id, rect)) => {
-                    self.profile_event(ScriptThreadEventCategory::SetViewport, || {
+                    self.profile_event(ScriptThreadEventCategory::SetViewport, Some(id), || {
                         self.handle_viewport(id, rect);
                     })
                 }
                 FromConstellation(ConstellationControlMsg::SetScrollState(id, scroll_state)) => {
-                    self.profile_event(ScriptThreadEventCategory::SetScrollState, || {
+                    self.profile_event(ScriptThreadEventCategory::SetScrollState, Some(id), || {
                         self.handle_set_scroll_state(id, &scroll_state);
                     })
                 }
@@ -1051,9 +1058,11 @@ impl ScriptThread {
         debug!("Processing events.");
         for msg in sequential {
             debug!("Processing event {:?}.", msg);
-            let category = self.categorize_msg(&msg);
 
-            let result = self.profile_event(category, move || {
+            let category = self.categorize_msg(&msg);
+            let pipeline_id = self.message_to_pipeline(&msg);
+
+            let result = self.profile_event(category, pipeline_id, move || {
                 match msg {
                     FromConstellation(ConstellationControlMsg::ExitScriptThread) => {
                         self.handle_exit_script_thread_msg();
@@ -1118,11 +1127,12 @@ impl ScriptThread {
                     _ => ScriptThreadEventCategory::ConstellationMsg
                 }
             },
+            // TODO https://github.com/servo/servo/issues/18998
             MixedMessage::FromDevtools(_) => ScriptThreadEventCategory::DevtoolsMsg,
             MixedMessage::FromImageCache(_) => ScriptThreadEventCategory::ImageCacheMsg,
             MixedMessage::FromScript(ref inner_msg) => {
                 match *inner_msg {
-                    MainThreadScriptMsg::Common(CommonScriptMsg::Task(category, _)) => {
+                    MainThreadScriptMsg::Common(CommonScriptMsg::Task(category, ..)) => {
                         category
                     },
                     MainThreadScriptMsg::RegisterPaintWorklet { .. } => {
@@ -1135,9 +1145,70 @@ impl ScriptThread {
         }
     }
 
-    fn profile_event<F, R>(&self, category: ScriptThreadEventCategory, f: F) -> R
+    fn message_to_pipeline(&self, msg: &MixedMessage) -> Option<PipelineId> {
+        use script_traits::ConstellationControlMsg::*;
+        match *msg {
+            MixedMessage::FromConstellation(ref inner_msg) => {
+                match *inner_msg {
+                    NavigationResponse(id, _) => Some(id),
+                    AttachLayout(ref new_layout_info) => Some(new_layout_info.new_pipeline_id),
+                    Resize(id, ..) => Some(id),
+                    ResizeInactive(id, ..) => Some(id),
+                    ExitPipeline(id, ..) => Some(id),
+                    ExitScriptThread => None,
+                    SendEvent(id, ..) => Some(id),
+                    Viewport(id, ..) => Some(id),
+                    SetScrollState(id, ..) => Some(id),
+                    GetTitle(id) => Some(id),
+                    SetDocumentActivity(id, ..) => Some(id),
+                    ChangeFrameVisibilityStatus(id, ..) => Some(id),
+                    NotifyVisibilityChange(id, ..) => Some(id),
+                    Navigate(id, ..) => Some(id),
+                    PostMessage(id, ..) => Some(id),
+                    MozBrowserEvent(id, ..) => Some(id),
+                    UpdatePipelineId(_, _, id, _) => Some(id),
+                    FocusIFrame(id, ..) => Some(id),
+                    WebDriverScriptCommand(id, ..) => Some(id),
+                    TickAllAnimations(id) => Some(id),
+                    // FIXME https://github.com/servo/servo/issues/15079
+                    TransitionEnd(..) => None,
+                    WebFontLoaded(id) => Some(id),
+                    DispatchIFrameLoadEvent { target: _, parent: id, child: _ } => Some(id),
+                    DispatchStorageEvent(id, ..) => Some(id),
+                    ReportCSSError(id, ..) => Some(id),
+                    Reload(id, ..) => Some(id),
+                    WebVREvents(id, ..) => Some(id),
+                    PaintMetric(..) => None,
+                }
+            },
+            MixedMessage::FromDevtools(_) => None,
+            MixedMessage::FromScript(ref inner_msg) => {
+                match *inner_msg {
+                    MainThreadScriptMsg::Common(CommonScriptMsg::Task(_, _, pipeline_id)) =>
+                        pipeline_id,
+                    MainThreadScriptMsg::Common(CommonScriptMsg::CollectReports(_)) => None,
+                    MainThreadScriptMsg::ExitWindow(pipeline_id) => Some(pipeline_id),
+                    MainThreadScriptMsg::Navigate(pipeline_id, ..) => Some(pipeline_id),
+                    MainThreadScriptMsg::WorkletLoaded(pipeline_id) => Some(pipeline_id),
+                    MainThreadScriptMsg::RegisterPaintWorklet { pipeline_id, .. } => Some(pipeline_id),
+                    MainThreadScriptMsg::DispatchJobQueue { .. }  => None,
+                }
+            },
+            MixedMessage::FromImageCache((pipeline_id, _)) => Some(pipeline_id),
+            MixedMessage::FromScheduler(ref timer_event) => {
+                let TimerEvent(source, _) = *timer_event;
+                match source {
+                    TimerSource::FromWindow(pipeline_id) => Some(pipeline_id),
+                    _ => None
+                }
+            }
+        }
+    }
+
+    fn profile_event<F, R>(&self, category: ScriptThreadEventCategory, pipeline_id: Option<PipelineId>, f: F) -> R
         where F: FnOnce() -> R {
-        if opts::get().profile_script_events {
+        let start = precise_time_ns();
+        let value = if opts::get().profile_script_events {
             let profiler_cat = match category {
                 ScriptThreadEventCategory::AttachLayout => ProfilerCategory::ScriptAttachLayout,
                 ScriptThreadEventCategory::ConstellationMsg => ProfilerCategory::ScriptConstellationMsg,
@@ -1172,8 +1243,18 @@ impl ScriptThread {
             profile(profiler_cat, None, self.time_profiler_chan.clone(), f)
         } else {
             f()
+        };
+        let end = precise_time_ns();
+        for (doc_id, doc) in self.documents.borrow().iter() {
+           if let Some(pipeline_id) = pipeline_id {
+                if pipeline_id == doc_id && end - start > MAX_TASK_NS {
+                    doc.start_tti();
                 }
             }
+            doc.record_tti_if_necessary();
+        }
+        value
+    }
 
     fn handle_msg_from_constellation(&self, msg: ConstellationControlMsg) {
         match msg {
@@ -1257,7 +1338,7 @@ impl ScriptThread {
             MainThreadScriptMsg::ExitWindow(id) => {
                 self.handle_exit_window_msg(id)
             },
-            MainThreadScriptMsg::Common(CommonScriptMsg::Task(_, task)) => {
+            MainThreadScriptMsg::Common(CommonScriptMsg::Task(_, task, _)) => {
                 task.run_box()
             }
             MainThreadScriptMsg::Common(CommonScriptMsg::CollectReports(chan)) => {
@@ -1725,12 +1806,24 @@ impl ScriptThread {
         let _ = self.chan.0.send(MainThreadScriptMsg::DispatchJobQueue { scope_url });
     }
 
-    pub fn dom_manipulation_task_source(&self) -> &DOMManipulationTaskSource {
+    pub fn dom_manipulation_task_source(&self, pipeline_id: PipelineId) -> DOMManipulationTaskSource {
-        &self.dom_manipulation_task_source
+        DOMManipulationTaskSource(self.dom_manipulation_task_sender.clone(), pipeline_id)
     }
 
-    pub fn performance_timeline_task_source(&self) -> &PerformanceTimelineTaskSource {
+    pub fn performance_timeline_task_source(&self, pipeline_id: PipelineId) -> PerformanceTimelineTaskSource {
-        &self.performance_timeline_task_source
+        PerformanceTimelineTaskSource(self.performance_timeline_task_sender.clone(), pipeline_id)
+    }
+
+    pub fn user_interaction_task_source(&self, pipeline_id: PipelineId) -> UserInteractionTaskSource {
+        UserInteractionTaskSource(self.user_interaction_task_sender.clone(), pipeline_id)
+    }
+
+    pub fn networking_task_source(&self, pipeline_id: PipelineId) -> NetworkingTaskSource {
+        NetworkingTaskSource(self.networking_task_sender.clone(), pipeline_id)
+    }
+
+    pub fn file_reading_task_source(&self, pipeline_id: PipelineId) -> FileReadingTaskSource {
+        FileReadingTaskSource(self.file_reading_task_sender.clone(), pipeline_id)
     }
 
     /// Handles a request for the window title.
@@ -2018,8 +2111,6 @@ impl ScriptThread {
         debug!("ScriptThread: loading {} on pipeline {:?}", incomplete.url, incomplete.pipeline_id);
 
         let MainThreadScriptChan(ref sender) = self.chan;
-        let DOMManipulationTaskSource(ref dom_sender) = self.dom_manipulation_task_source;
-        let UserInteractionTaskSource(ref user_sender) = self.user_interaction_task_source;
         let HistoryTraversalTaskSource(ref history_sender) = self.history_traversal_task_source;
 
         let (ipc_timer_event_chan, ipc_timer_event_port) = ipc::channel().unwrap();
@@ -2041,12 +2132,12 @@ impl ScriptThread {
         let window = Window::new(
             self.js_runtime.clone(),
             MainThreadScriptChan(sender.clone()),
-            DOMManipulationTaskSource(dom_sender.clone()),
+            self.dom_manipulation_task_source(incomplete.pipeline_id),
-            UserInteractionTaskSource(user_sender.clone()),
+            self.user_interaction_task_source(incomplete.pipeline_id),
-            self.networking_task_source.clone(),
+            self.networking_task_source(incomplete.pipeline_id),
             HistoryTraversalTaskSource(history_sender.clone()),
-            self.file_reading_task_source.clone(),
+            self.file_reading_task_source(incomplete.pipeline_id),
-            self.performance_timeline_task_source.clone(),
+            self.performance_timeline_task_source(incomplete.pipeline_id).clone(),
             self.image_cache_channel.clone(),
             self.image_cache.clone(),
             self.resource_threads.clone(),
@@ -2563,7 +2654,7 @@ impl ScriptThread {
 
     fn handle_paint_metric(&self,
                            pipeline_id: PipelineId,
-                           metric_type: PaintMetricType,
+                           metric_type: ProgressiveWebMetricType,
                            metric_value: f64) {
         let window = self.documents.borrow().find_window(pipeline_id);
         if let Some(window) = window {

components/script/serviceworkerjob.rs

@@ -153,19 +153,21 @@ impl JobQueue {
     // https://w3c.github.io/ServiceWorker/#register-algorithm
     fn run_register(&self, job: &Job, scope_url: ServoUrl, script_thread: &ScriptThread) {
         debug!("running register job");
+        let global = &*job.client.global();
+        let pipeline_id = global.pipeline_id();
         // Step 1-3
         if !UrlHelper::is_origin_trustworthy(&job.script_url) {
             // Step 1.1
             reject_job_promise(job,
                                Error::Type("Invalid script ServoURL".to_owned()),
-                               script_thread.dom_manipulation_task_source());
+                               &script_thread.dom_manipulation_task_source(pipeline_id));
             // Step 1.2 (see run_job)
             return;
         } else if job.script_url.origin() != job.referrer.origin() || job.scope_url.origin() != job.referrer.origin() {
             // Step 2.1/3.1
             reject_job_promise(job,
                                Error::Security,
-                               script_thread.dom_manipulation_task_source());
+                               &script_thread.dom_manipulation_task_source(pipeline_id));
             // Step 2.2/3.2 (see run_job)
             return;
         }
@@ -180,17 +182,15 @@ impl JobQueue {
             if let Some(ref newest_worker) = reg.get_newest_worker() {
                 if (&*newest_worker).get_script_url() == job.script_url {
                     // Step 5.3.1
-                    resolve_job_promise(job, &*reg, script_thread.dom_manipulation_task_source());
+                    resolve_job_promise(job, &*reg, &script_thread.dom_manipulation_task_source(pipeline_id));
                     // Step 5.3.2 (see run_job)
                     return;
                 }
             }
         } else {
             // Step 6.1
-            let global = &*job.client.global();
-            let pipeline = global.pipeline_id();
             let new_reg = ServiceWorkerRegistration::new(&*global, &job.script_url, scope_url);
-            script_thread.handle_serviceworker_registration(&job.scope_url, &*new_reg, pipeline);
+            script_thread.handle_serviceworker_registration(&job.scope_url, &*new_reg, pipeline_id);
         }
         // Step 7
         self.update(job, script_thread)
@@ -218,13 +218,16 @@ impl JobQueue {
     // https://w3c.github.io/ServiceWorker/#update-algorithm
     fn update(&self, job: &Job, script_thread: &ScriptThread) {
         debug!("running update job");
+
+        let global = &*job.client.global();
+        let pipeline_id = global.pipeline_id();
         // Step 1
         let reg = match script_thread.handle_get_registration(&job.scope_url) {
             Some(reg) => reg,
             None => {
                 let err_type = Error::Type("No registration to update".to_owned());
                 // Step 2.1
-                reject_job_promise(job, err_type, script_thread.dom_manipulation_task_source());
+                reject_job_promise(job, err_type, &script_thread.dom_manipulation_task_source(pipeline_id));
                 // Step 2.2 (see run_job)
                 return;
             }
@@ -233,7 +236,7 @@ impl JobQueue {
         if reg.get_uninstalling() {
             let err_type = Error::Type("Update called on an uninstalling registration".to_owned());
             // Step 2.1
-            reject_job_promise(job, err_type, script_thread.dom_manipulation_task_source());
+            reject_job_promise(job, err_type, &script_thread.dom_manipulation_task_source(pipeline_id));
             // Step 2.2 (see run_job)
             return;
         }
@@ -244,7 +247,7 @@ impl JobQueue {
         if newest_worker_url.as_ref() == Some(&job.script_url)  && job.job_type == JobType::Update {
             let err_type = Error::Type("Invalid script ServoURL".to_owned());
             // Step 4.1
-            reject_job_promise(job, err_type, script_thread.dom_manipulation_task_source());
+            reject_job_promise(job, err_type, &script_thread.dom_manipulation_task_source(pipeline_id));
             // Step 4.2 (see run_job)
             return;
         }
@@ -252,7 +255,7 @@ impl JobQueue {
         if let Some(newest_worker) = newest_worker {
             job.client.set_controller(&*newest_worker);
             // Step 8.1
-            resolve_job_promise(job, &*reg, script_thread.dom_manipulation_task_source());
+            resolve_job_promise(job, &*reg, &script_thread.dom_manipulation_task_source(pipeline_id));
             // Step 8.2 present in run_job
         }
         // TODO Step 9 (create new service worker)

components/script/task_source/dom_manipulation.rs

@@ -7,6 +7,7 @@ use dom::bindings::refcounted::Trusted;
 use dom::event::{EventBubbles, EventCancelable, EventTask, SimpleEventTask};
 use dom::eventtarget::EventTarget;
 use dom::window::Window;
+use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::MainThreadScriptMsg;
 use servo_atoms::Atom;
@@ -17,7 +18,7 @@ use task::{TaskCanceller, TaskOnce};
 use task_source::TaskSource;
 
 #[derive(Clone, JSTraceable)]
-pub struct DOMManipulationTaskSource(pub Sender<MainThreadScriptMsg>);
+pub struct DOMManipulationTaskSource(pub Sender<MainThreadScriptMsg>, pub PipelineId);
 
 impl fmt::Debug for DOMManipulationTaskSource {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -37,6 +38,7 @@ impl TaskSource for DOMManipulationTaskSource {
         let msg = MainThreadScriptMsg::Common(CommonScriptMsg::Task(
             ScriptThreadEventCategory::ScriptEvent,
             Box::new(canceller.wrap_task(task)),
+            Some(self.1)
         ));
         self.0.send(msg).map_err(|_| ())
     }

components/script/task_source/file_reading.rs

@@ -4,17 +4,18 @@
 
 use dom::domexception::DOMErrorName;
 use dom::filereader::{FileReader, TrustedFileReader, GenerationId, ReadMetaData};
+use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory, ScriptChan};
 use std::sync::Arc;
 use task::{TaskCanceller, TaskOnce};
 use task_source::TaskSource;
 
 #[derive(JSTraceable)]
-pub struct FileReadingTaskSource(pub Box<ScriptChan + Send + 'static>);
+pub struct FileReadingTaskSource(pub Box<ScriptChan + Send + 'static>, pub PipelineId);
 
 impl Clone for FileReadingTaskSource {
     fn clone(&self) -> FileReadingTaskSource {
-        FileReadingTaskSource(self.0.clone())
+        FileReadingTaskSource(self.0.clone(), self.1.clone())
     }
 }
 
@@ -30,6 +31,7 @@ impl TaskSource for FileReadingTaskSource {
         self.0.send(CommonScriptMsg::Task(
             ScriptThreadEventCategory::FileRead,
             Box::new(canceller.wrap_task(task)),
+            Some(self.1),
         ))
     }
 }

components/script/task_source/networking.rs

@@ -2,16 +2,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
 use task::{TaskCanceller, TaskOnce};
 use task_source::TaskSource;
 
 #[derive(JSTraceable)]
-pub struct NetworkingTaskSource(pub Box<ScriptChan + Send + 'static>);
+pub struct NetworkingTaskSource(pub Box<ScriptChan + Send + 'static>, pub PipelineId);
 
 impl Clone for NetworkingTaskSource {
     fn clone(&self) -> NetworkingTaskSource {
-        NetworkingTaskSource(self.0.clone())
+        NetworkingTaskSource(self.0.clone(), self.1.clone())
     }
 }
 
@@ -27,6 +28,7 @@ impl TaskSource for NetworkingTaskSource {
         self.0.send(CommonScriptMsg::Task(
             ScriptThreadEventCategory::NetworkEvent,
             Box::new(canceller.wrap_task(task)),
+            Some(self.1),
         ))
     }
 }
@@ -41,6 +43,7 @@ impl NetworkingTaskSource {
         self.0.send(CommonScriptMsg::Task(
             ScriptThreadEventCategory::NetworkEvent,
             Box::new(task),
+            Some(self.1),
         ))
     }
 }

components/script/task_source/performance_timeline.rs

@@ -8,6 +8,7 @@
 
 use dom::bindings::refcounted::Trusted;
 use dom::globalscope::GlobalScope;
+use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
 use std::fmt;
 use std::result::Result;
@@ -15,11 +16,11 @@ use task::{TaskCanceller, TaskOnce};
 use task_source::TaskSource;
 
 #[derive(JSTraceable)]
-pub struct PerformanceTimelineTaskSource(pub Box<ScriptChan + Send + 'static>);
+pub struct PerformanceTimelineTaskSource(pub Box<ScriptChan + Send + 'static>, pub PipelineId);
 
 impl Clone for PerformanceTimelineTaskSource {
     fn clone(&self) -> PerformanceTimelineTaskSource {
-        PerformanceTimelineTaskSource(self.0.clone())
+        PerformanceTimelineTaskSource(self.0.clone(), self.1.clone())
     }
 }
 
@@ -40,7 +41,8 @@ impl TaskSource for PerformanceTimelineTaskSource {
     {
         let msg = CommonScriptMsg::Task(
             ScriptThreadEventCategory::PerformanceTimelineTask,
-            Box::new(canceller.wrap_task(task))
+            Box::new(canceller.wrap_task(task)),
+            Some(self.1)
         );
         self.0.send(msg).map_err(|_| ())
     }

components/script/task_source/user_interaction.rs

@@ -7,6 +7,7 @@ use dom::bindings::refcounted::Trusted;
 use dom::event::{EventBubbles, EventCancelable, EventTask};
 use dom::eventtarget::EventTarget;
 use dom::window::Window;
+use msg::constellation_msg::PipelineId;
 use script_runtime::{CommonScriptMsg, ScriptThreadEventCategory};
 use script_thread::MainThreadScriptMsg;
 use servo_atoms::Atom;
@@ -17,7 +18,7 @@ use task::{TaskCanceller, TaskOnce};
 use task_source::TaskSource;
 
 #[derive(Clone, JSTraceable)]
-pub struct UserInteractionTaskSource(pub Sender<MainThreadScriptMsg>);
+pub struct UserInteractionTaskSource(pub Sender<MainThreadScriptMsg>, pub PipelineId);
 
 impl fmt::Debug for UserInteractionTaskSource {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -37,6 +38,7 @@ impl TaskSource for UserInteractionTaskSource {
         let msg = MainThreadScriptMsg::Common(CommonScriptMsg::Task(
             ScriptThreadEventCategory::InputEvent,
             Box::new(canceller.wrap_task(task)),
+            Some(self.1)
         ));
         self.0.send(msg).map_err(|_| ())
     }

components/script_traits/lib.rs

@@ -231,13 +231,15 @@ pub enum DocumentActivity {
     FullyActive,
 }
 
-/// The type of recorded paint metric.
+/// Type of recorded progressive web metric
-#[derive(Deserialize, Serialize)]
+#[derive(Clone, Copy, Debug, Deserialize, Serialize)]
-pub enum PaintMetricType {
+pub enum ProgressiveWebMetricType {
-    /// Time to First Paint type.
+    /// Time to first Paint
     FirstPaint,
-    /// Time to First Contentful Paint type.
+    /// Time to first contentful paint
     FirstContentfulPaint,
+    /// Time to interactive
+    TimeToInteractive,
 }
 
 /// The reason why the pipeline id of an iframe is being updated.
@@ -322,7 +324,7 @@ pub enum ConstellationControlMsg {
     /// Notifies the script thread of WebVR events.
     WebVREvents(PipelineId, Vec<WebVREvent>),
     /// Notifies the script thread about a new recorded paint metric.
-    PaintMetric(PipelineId, PaintMetricType, f64),
+    PaintMetric(PipelineId, ProgressiveWebMetricType, f64),
 }
 
 impl fmt::Debug for ConstellationControlMsg {

tests/unit/metrics/interactive_time.rs

@@ -0,0 +1,112 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use ipc_channel::ipc;
+use metrics::{InteractiveMetrics, InteractiveFlag, InteractiveWindow};
+use metrics::{ProfilerMetadataFactory, ProgressiveWebMetric};
+use profile_traits::time::{ProfilerChan, TimerMetadata};
+use time;
+
+struct DummyProfilerMetadataFactory {}
+impl ProfilerMetadataFactory for DummyProfilerMetadataFactory {
+    fn new_metadata(&self) -> Option<TimerMetadata> {
+        None
+    }
+}
+
+
+fn test_interactive() -> InteractiveMetrics {
+    let (sender, _) = ipc::channel().unwrap();
+    let profiler_chan = ProfilerChan(sender);
+    let mut interactive = InteractiveMetrics::new(profiler_chan);
+
+    assert_eq!((&interactive).get_navigation_start(), None);
+    assert_eq!(interactive.get_tti(), None);
+
+    interactive.set_navigation_start(time::precise_time_ns() as f64);
+
+    interactive
+}
+
+#[test]
+fn test_set_dcl() {
+    let profiler_metadata_factory = DummyProfilerMetadataFactory {};
+
+    let interactive = test_interactive();
+    interactive.maybe_set_tti(&profiler_metadata_factory, InteractiveFlag::DOMContentLoaded);
+    let dcl = interactive.get_dom_content_loaded();
+    assert!(dcl.is_some());
+
+    //try to overwrite
+    interactive.maybe_set_tti(&profiler_metadata_factory, InteractiveFlag::DOMContentLoaded);
+    assert_eq!(interactive.get_dom_content_loaded(), dcl);
+    assert_eq!(interactive.get_tti(), None);
+}
+
+#[test]
+fn test_set_mta() {
+    let profiler_metadata_factory = DummyProfilerMetadataFactory {};
+
+    let interactive = test_interactive();
+    let t = time::precise_time_ns();
+    interactive.maybe_set_tti(
+        &profiler_metadata_factory,
+        InteractiveFlag::TimeToInteractive(t as f64),
+    );
+    let mta = interactive.get_main_thread_available();
+    assert!(mta.is_some());
+    assert_eq!(mta, Some(t as f64));
+
+    //try to overwrite
+    interactive.maybe_set_tti(
+        &profiler_metadata_factory,
+        InteractiveFlag::TimeToInteractive(time::precise_time_ns() as f64),
+    );
+    assert_eq!(interactive.get_main_thread_available(), mta);
+    assert_eq!(interactive.get_tti(), None);
+}
+
+#[test]
+fn test_set_tti_dcl() {
+    let profiler_metadata_factory = DummyProfilerMetadataFactory {};
+
+    let interactive = test_interactive();
+    let t = time::precise_time_ns();
+    interactive.maybe_set_tti(
+        &profiler_metadata_factory,
+        InteractiveFlag::TimeToInteractive(t as f64),
+    );
+    let mta = interactive.get_main_thread_available();
+    assert!(mta.is_some());
+
+    interactive.maybe_set_tti(&profiler_metadata_factory, InteractiveFlag::DOMContentLoaded);
+    let dcl = interactive.get_dom_content_loaded();
+    assert!(dcl.is_some());
+
+    let interactive_time = dcl.unwrap() - (&interactive).get_navigation_start().unwrap();
+    assert_eq!(interactive.get_tti(), Some(interactive_time));
+}
+
+#[test]
+fn test_set_tti_mta() {
+    let profiler_metadata_factory = DummyProfilerMetadataFactory {};
+
+    let interactive = test_interactive();
+    interactive.maybe_set_tti(&profiler_metadata_factory, InteractiveFlag::DOMContentLoaded);
+    let dcl = interactive.get_dom_content_loaded();
+    assert!(dcl.is_some());
+
+    let t = time::precise_time_ns();
+    interactive.maybe_set_tti(
+        &profiler_metadata_factory,
+        InteractiveFlag::TimeToInteractive(t as f64),
+    );
+    let mta = interactive.get_main_thread_available();
+    assert!(mta.is_some());
+
+    let interactive_time = mta.unwrap() - (&interactive).get_navigation_start().unwrap();
+    assert_eq!(interactive.get_tti(), Some(interactive_time));
+}
+
+// TODO InteractiveWindow tests

tests/unit/metrics/lib.rs

@@ -13,5 +13,7 @@ extern crate profile_traits;
 extern crate style;
 extern crate time;
 
+#[cfg(test)]
+mod interactive_time;
 #[cfg(test)]
 mod paint_time;

tests/unit/metrics/paint_time.rs

@@ -7,7 +7,7 @@ use gfx::display_list::{BaseDisplayItem, WebRenderImageInfo};
 use gfx::display_list::{DisplayItem, DisplayList, ImageDisplayItem};
 use gfx_traits::Epoch;
 use ipc_channel::ipc;
-use metrics::{PaintTimeMetrics, ProfilerMetadataFactory};
+use metrics::{PaintTimeMetrics, ProfilerMetadataFactory, ProgressiveWebMetric};
 use msg::constellation_msg::TEST_PIPELINE_ID;
 use net_traits::image::base::PixelFormat;
 use profile_traits::time::{ProfilerChan, TimerMetadata};
@@ -27,10 +27,27 @@ fn test_paint_metrics_construction() {
     let profiler_chan = ProfilerChan(sender);
     let (layout_sender, _) = ipc::channel().unwrap();
     let (script_sender, _) = ipc::channel().unwrap();
-    let paint_time_metrics = PaintTimeMetrics::new(TEST_PIPELINE_ID, profiler_chan, layout_sender, script_sender);
+    let paint_time_metrics = PaintTimeMetrics::new(
-    assert_eq!(paint_time_metrics.get_navigation_start(), None, "navigation start is None");
+        TEST_PIPELINE_ID,
-    assert_eq!(paint_time_metrics.get_first_paint(), None, "first paint is None");
+        profiler_chan,
-    assert_eq!(paint_time_metrics.get_first_contentful_paint(), None, "first contentful paint is None");
+        layout_sender,
+        script_sender,
+    );
+    assert_eq!(
+        (&paint_time_metrics).get_navigation_start(),
+        None,
+        "navigation start is None"
+    );
+    assert_eq!(
+        paint_time_metrics.get_first_paint(),
+        None,
+        "first paint is None"
+    );
+    assert_eq!(
+        paint_time_metrics.get_first_contentful_paint(),
+        None,
+        "first contentful paint is None"
+    );
 }
 
 fn test_common(display_list: &DisplayList, epoch: Epoch) -> PaintTimeMetrics {
@@ -38,22 +55,40 @@ fn test_common(display_list: &DisplayList, epoch: Epoch) -> PaintTimeMetrics {
     let profiler_chan = ProfilerChan(sender);
     let (layout_sender, _) = ipc::channel().unwrap();
     let (script_sender, _) = ipc::channel().unwrap();
-    let mut paint_time_metrics = PaintTimeMetrics::new(TEST_PIPELINE_ID, profiler_chan, layout_sender, script_sender);
+    let mut paint_time_metrics = PaintTimeMetrics::new(
+        TEST_PIPELINE_ID,
+        profiler_chan,
+        layout_sender,
+        script_sender,
+    );
     let dummy_profiler_metadata_factory = DummyProfilerMetadataFactory {};
 
-    paint_time_metrics.maybe_observe_paint_time(&dummy_profiler_metadata_factory,
+    paint_time_metrics.maybe_observe_paint_time(
+        &dummy_profiler_metadata_factory,
         epoch,
-                                                &display_list);
+        &display_list,
+    );
 
     // Should not set any metric until navigation start is set.
     paint_time_metrics.maybe_set_metric(epoch, 0.);
-    assert_eq!(paint_time_metrics.get_first_paint(), None, "first paint is None");
+    assert_eq!(
-    assert_eq!(paint_time_metrics.get_first_contentful_paint(), None, "first contentful paint is None");
+        paint_time_metrics.get_first_paint(),
+        None,
+        "first paint is None"
+    );
+    assert_eq!(
+        paint_time_metrics.get_first_contentful_paint(),
+        None,
+        "first contentful paint is None"
+    );
 
     let navigation_start = time::precise_time_ns() as f64;
     paint_time_metrics.set_navigation_start(navigation_start);
-    assert_eq!(paint_time_metrics.get_navigation_start().unwrap(),
+    assert_eq!(
-               navigation_start, "navigation start is set");
+        (&paint_time_metrics).get_navigation_start().unwrap(),
+        navigation_start,
+        "navigation start is set"
+    );
 
     paint_time_metrics
 }
@@ -65,11 +100,18 @@ fn test_first_paint_setter() {
         clip_scroll_nodes: Vec::new(),
     };
     let epoch = Epoch(0);
-    let mut paint_time_metrics = test_common(&empty_display_list, epoch);
+    let paint_time_metrics = test_common(&empty_display_list, epoch);
     let now = time::precise_time_ns() as f64;
     paint_time_metrics.maybe_set_metric(epoch, now);
-    assert!(paint_time_metrics.get_first_paint().is_some(), "first paint is set");
+    assert!(
-    assert_eq!(paint_time_metrics.get_first_contentful_paint(), None, "first contentful paint is None");
+        paint_time_metrics.get_first_paint().is_some(),
+        "first paint is set"
+    );
+    assert_eq!(
+        paint_time_metrics.get_first_contentful_paint(),
+        None,
+        "first contentful paint is None"
+    );
 }
 
 #[test]
@@ -92,9 +134,15 @@ fn test_first_contentful_paint_setter() {
         clip_scroll_nodes: Vec::new(),
     };
     let epoch = Epoch(0);
-    let mut paint_time_metrics = test_common(&display_list, epoch);
+    let paint_time_metrics = test_common(&display_list, epoch);
     let now = time::precise_time_ns() as f64;
     paint_time_metrics.maybe_set_metric(epoch, now);
-    assert!(paint_time_metrics.get_first_contentful_paint().is_some(), "first contentful paint is set");
+    assert!(
-    assert!(paint_time_metrics.get_first_paint().is_some(), "first paint is set");
+        paint_time_metrics.get_first_contentful_paint().is_some(),
+        "first contentful paint is set"
+    );
+    assert!(
+        paint_time_metrics.get_first_paint().is_some(),
+        "first paint is set"
+    );
 }