Auto merge of #18155 - ferjm:pwm.perf.timeline, r=jdm

Add paint metrics to Performance Timeline API

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #18111
- [X] There are tests for these changes

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components/script/dom/mod.rs

@@ -401,6 +401,7 @@ pub mod performance;
 pub mod performanceentry;
 pub mod performanceobserver;
 pub mod performanceobserverentrylist;
+pub mod performancepainttiming;
 pub mod performancetiming;
 pub mod permissions;
 pub mod permissionstatus;

components/script/dom/performanceentry.rs

@@ -21,10 +21,10 @@ pub struct PerformanceEntry {
 }
 
 impl PerformanceEntry {
-    fn new_inherited(name: DOMString,
-                     entry_type: DOMString,
-                     start_time: f64,
-                     duration: f64) -> PerformanceEntry {
+    pub fn new_inherited(name: DOMString,
+                         entry_type: DOMString,
+                         start_time: f64,
+                         duration: f64) -> PerformanceEntry {
         PerformanceEntry {
             reflector_: Reflector::new(),
             name,

components/script/dom/performanceobserver.rs

@@ -27,7 +27,7 @@ const VALID_ENTRY_TYPES: &'static [&'static str] = &[
     // "measure", XXX User Timing API
     // "resource", XXX Resource Timing API
     // "server", XXX Server Timing API
-    // "paint", XXX Paint Timing API
+    "paint", // Paint Timing API
 ];
 
 #[dom_struct]

components/script/dom/performancepainttiming.rs

@@ -0,0 +1,41 @@
+/* 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 dom::bindings::codegen::Bindings::PerformancePaintTimingBinding;
+use dom::bindings::js::Root;
+use dom::bindings::reflector::reflect_dom_object;
+use dom::bindings::str::DOMString;
+use dom::globalscope::GlobalScope;
+use dom::performanceentry::PerformanceEntry;
+use dom_struct::dom_struct;
+use script_traits::PaintMetricType;
+
+#[dom_struct]
+pub struct PerformancePaintTiming {
+    entry: PerformanceEntry,
+}
+
+impl PerformancePaintTiming {
+    fn new_inherited(metric_type: PaintMetricType, start_time: f64)
+        -> PerformancePaintTiming {
+        let name = match metric_type {
+            PaintMetricType::FirstPaint => DOMString::from("first-paint"),
+            PaintMetricType::FirstContentfulPaint => DOMString::from("first-contentful-paint"),
+        };
+        PerformancePaintTiming {
+            entry: PerformanceEntry::new_inherited(name,
+                                                   DOMString::from("paint"),
+                                                   start_time,
+                                                   0.)
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(global: &GlobalScope,
+               metric_type: PaintMetricType,
+               start_time: f64) -> Root<PerformancePaintTiming> {
+        let entry = PerformancePaintTiming::new_inherited(metric_type, start_time);
+        reflect_dom_object(box entry, global, PerformancePaintTimingBinding::Wrap)
+    }
+}

components/script/dom/webidls/PerformancePaintTiming.webidl

@@ -0,0 +1,11 @@
+/* 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/.
+ *
+ * The origin of this IDL file is
+ * https://wicg.github.io/paint-timing/#sec-PerformancePaintTiming
+ */
+
+[Exposed=(Window,Worker)]
+interface PerformancePaintTiming : PerformanceEntry {
+};