DevTools: Switch to using fast stack iterator to collect stacks during timeline recording.

third_party/WebKit/LayoutTests/http/tests/inspector/timeline-test.js

 var initialize_Timeline = function() {
 
 InspectorTest.preloadPanel("timeline");
 WebInspector.TempFile = InspectorTest.TempFileMock;
 
 // Scrub values when printing out these properties in the record or data field.
 InspectorTest.timelinePropertyFormatters = {
     children: "formatAsTypeName",
     endTime: "formatAsTypeName",
     requestId: "formatAsTypeName",
@@ skipping 62 matching lines @@
 
 InspectorTest.startTimeline = function(callback)
 {
     var panel = WebInspector.panels.timeline;
     function onRecordingStarted()
     {
         panel._model.removeEventListener(WebInspector.TimelineModel.Events.RecordingStarted, onRecordingStarted, this)
         callback();
     }
     panel._model.addEventListener(WebInspector.TimelineModel.Events.RecordingStarted, onRecordingStarted, this)
-    panel._captureJSProfileSetting.set(false);
+    panel._captureJSProfileSetting.set(true);

[caseq, 2016/01/25 19:18:36]

Hm... Looks like we can't do this before we fix "children are longer than
parent" problem, otherwise the test will become way more flaky.

[alph, 2016/01/26 00:58:49]

The patch addresses this issue as well.

     panel._toggleRecording();
 };
 
 InspectorTest.stopTimeline = function(callback)
 {
     var panel = WebInspector.panels.timeline;
     function didStop()
     {
         panel._model.removeEventListener(WebInspector.TimelineModel.Events.RecordingStopped, didStop, this)
         InspectorTest.runAfterPendingDispatches(callback);
@@ skipping 305 matching lines @@
         if (!--count) {
             callback();
             return;
         }
         if (window.testRunner)
             testRunner.capturePixelsAsyncThen(requestAnimationFrame.bind(window, makeFrame));
         else
             window.requestAnimationFrame(makeFrame);
     }
 }