Use "measured_frame" instead of "CrRendererMain" to detect process ID (#53969)
diff --git a/dev/devicelab/lib/framework/browser.dart b/dev/devicelab/lib/framework/browser.dart
index 47f3ebb..1be9155 100644
--- a/dev/devicelab/lib/framework/browser.dart
+++ b/dev/devicelab/lib/framework/browser.dart
@@ -281,11 +281,26 @@
.toList()
..sort((BlinkTraceEvent a, BlinkTraceEvent b) => a.ts - b.ts);
+ // Use the pid from the first "measured_frame" event since the event is
+ // emitted by the script running on the process we're interested in.
+ //
+ // We previously tried using the "CrRendererMain" event. However, for
+ // reasons unknown, Chrome in the devicelab refuses to emit this event
+ // sometimes, causing to flakes.
+ final BlinkTraceEvent firstMeasuredFrameEvent = events.firstWhere(
+ (BlinkTraceEvent event) => event.isBeginMeasuredFrame,
+ orElse: () => null,
+ );
+
+ if (firstMeasuredFrameEvent == null) {
+ // This happens in benchmarks that do not measure frames, such as some
+ // of the text layout benchmarks.
+ return null;
+ }
+
+ final int tabPid = firstMeasuredFrameEvent.pid;
+
// Filter out data from unrelated processes
- final BlinkTraceEvent processLabel = events
- .where((BlinkTraceEvent event) => event.isCrRendererMain)
- .single;
- final int tabPid = processLabel.pid;
events = events.where((BlinkTraceEvent element) => element.pid == tabPid).toList();
// Extract frame data.
@@ -489,14 +504,6 @@
/// This event is a duration event that has its `tdur` populated.
bool get isUpdateAllLifecyclePhases => ph == 'X' && name == 'WebViewImpl::updateAllLifecyclePhases';
- /// A "CrRendererMain" event contains information about the browser's UI
- /// thread.
- ///
- /// This event's [pid] field identifies the process that performs web page
- /// rendering. The [isBeginFrame] and [isUpdateAllLifecyclePhases] events
- /// with the same [pid] as this event all belong to the same web page.
- bool get isCrRendererMain => name == 'thread_name' && args['name'] == 'CrRendererMain';
-
/// Whether this is the beginning of a "measured_frame" event.
///
/// This event is a custom event emitted by our benchmark test harness.
