Auto merge of #20307 - csmoe:measure_query_time, r=jdm

Measure time required before a layout query is serviced by the layout thread

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- [X] extract QueryMsg from ReflowGoal
- [X] introduce QueryMsg timestamp

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [x] These changes fix #19795 (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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components/script_layout_interface/Cargo.toml

@@ -20,6 +20,7 @@ html5ever = "0.22"
 ipc-channel = "0.10"
 libc = "0.2"
 log = "0.3.5"
+time = "0.1.17"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 metrics = {path = "../metrics"}

components/script_layout_interface/message.rs

@@ -2,7 +2,7 @@
  * 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 {OpaqueStyleAndLayoutData, TrustedNodeAddress, PendingImage};
+use {OpaqueStyleAndLayoutData, PendingImage, TrustedNodeAddress};
 use app_units::Au;
 use euclid::{Point2D, Rect};
 use gfx_traits::Epoch;
@@ -106,11 +106,8 @@ pub enum NodesFromPointQueryType {
     Topmost,
 }
 
-/// Any query to perform with this reflow.
 #[derive(Debug, PartialEq)]
-pub enum ReflowGoal {
-    Full,
-    TickAnimations,
+pub enum QueryMsg {
     ContentBoxQuery(TrustedNodeAddress),
     ContentBoxesQuery(TrustedNodeAddress),
     NodeScrollIdQuery(TrustedNodeAddress),
@@ -124,19 +121,33 @@ pub enum ReflowGoal {
     ElementInnerTextQuery(TrustedNodeAddress),
 }
 
+/// Any query to perform with this reflow.
+#[derive(Debug, PartialEq)]
+pub enum ReflowGoal {
+    Full,
+    TickAnimations,
+    LayoutQuery(QueryMsg, u64),
+}
+
 impl ReflowGoal {
     /// Returns true if the given ReflowQuery needs a full, up-to-date display list to
     /// be present or false if it only needs stacking-relative positions.
     pub fn needs_display_list(&self) -> bool {
         match *self {
-            ReflowGoal::NodesFromPointQuery(..) | ReflowGoal::TextIndexQuery(..) |
-            ReflowGoal::TickAnimations | ReflowGoal::ElementInnerTextQuery(_) |
-            ReflowGoal::Full => true,
-            ReflowGoal::ContentBoxQuery(_) | ReflowGoal::ContentBoxesQuery(_) |
-            ReflowGoal::NodeGeometryQuery(_) | ReflowGoal::NodeScrollGeometryQuery(_) |
-            ReflowGoal::NodeScrollIdQuery(_) |
-            ReflowGoal::ResolvedStyleQuery(..) | ReflowGoal::OffsetParentQuery(_) |
-            ReflowGoal::StyleQuery(_) => false,
+            ReflowGoal::Full | ReflowGoal::TickAnimations => true,
+            ReflowGoal::LayoutQuery(ref querymsg, _) => match querymsg {
+                &QueryMsg::NodesFromPointQuery(..) |
+                &QueryMsg::TextIndexQuery(..) |
+                &QueryMsg::ElementInnerTextQuery(_) => true,
+                &QueryMsg::ContentBoxQuery(_) |
+                &QueryMsg::ContentBoxesQuery(_) |
+                &QueryMsg::NodeGeometryQuery(_) |
+                &QueryMsg::NodeScrollGeometryQuery(_) |
+                &QueryMsg::NodeScrollIdQuery(_) |
+                &QueryMsg::ResolvedStyleQuery(..) |
+                &QueryMsg::OffsetParentQuery(_) |
+                &QueryMsg::StyleQuery(_) => false,
+            },
         }
     }
 
@@ -144,14 +155,20 @@ impl ReflowGoal {
     /// false if a layout_thread display list is sufficient.
     pub fn needs_display(&self) -> bool {
         match *self {
-            ReflowGoal::StyleQuery(_)  | ReflowGoal::TextIndexQuery(..) |
-            ReflowGoal::ContentBoxQuery(_) | ReflowGoal::ContentBoxesQuery(_) |
-            ReflowGoal::NodeGeometryQuery(_) | ReflowGoal::NodeScrollGeometryQuery(_) |
-            ReflowGoal::NodeScrollIdQuery(_) | ReflowGoal::ResolvedStyleQuery(..) |
-            ReflowGoal::OffsetParentQuery(_) => false,
-            ReflowGoal::NodesFromPointQuery(..) | ReflowGoal::Full |
-            ReflowGoal::ElementInnerTextQuery(_) |
-            ReflowGoal::TickAnimations => true,
+            ReflowGoal::Full | ReflowGoal::TickAnimations => true,
+            ReflowGoal::LayoutQuery(ref querymsg, _) => match querymsg {
+                &QueryMsg::NodesFromPointQuery(..) |
+                &QueryMsg::TextIndexQuery(..) |
+                &QueryMsg::ElementInnerTextQuery(_) => true,
+                &QueryMsg::ContentBoxQuery(_) |
+                &QueryMsg::ContentBoxesQuery(_) |
+                &QueryMsg::NodeGeometryQuery(_) |
+                &QueryMsg::NodeScrollGeometryQuery(_) |
+                &QueryMsg::NodeScrollIdQuery(_) |
+                &QueryMsg::ResolvedStyleQuery(..) |
+                &QueryMsg::OffsetParentQuery(_) |
+                &QueryMsg::StyleQuery(_) => false,
+            },
         }
     }
 }