Timeline: add experiment to show events from subframes in the frames of their own

third_party/WebKit/Source/devtools/front_end/main/Main.js

Index: third_party/WebKit/Source/devtools/front_end/main/Main.js
diff --git a/third_party/WebKit/Source/devtools/front_end/main/Main.js b/third_party/WebKit/Source/devtools/front_end/main/Main.js
index ed8201d321f36f6902f1eaa904224a441e07b097..8bcf744d53f155b290730841417485f8dcd053fd 100644
--- a/third_party/WebKit/Source/devtools/front_end/main/Main.js
+++ b/third_party/WebKit/Source/devtools/front_end/main/Main.js
@@ -119,6 +119,7 @@ WebInspector.Main = class {
     Runtime.experiments.register('timelineTracingJSProfile', 'Timeline tracing based JS profiler', true);
     Runtime.experiments.register('timelineV8RuntimeCallStats', 'V8 Runtime Call Stats on Timeline', true);
     Runtime.experiments.register('timelineRuleUsageRecording', 'Track CSS rules usage while recording Timeline.');
+    Runtime.experiments.register('timelinePerFrameTrack', 'Show track per frame on Timeline', true);
 
     Runtime.experiments.cleanUpStaleExperiments();