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

third_party/WebKit/Source/devtools/front_end/timeline/TimelineJSProfile.js

Index: third_party/WebKit/Source/devtools/front_end/timeline/TimelineJSProfile.js
diff --git a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineJSProfile.js b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineJSProfile.js
index cf1907a68f7db801e798a5170f9a587e485d6cda..130dc9fce6fdd1180549b00b172b332b77db7eba 100644
--- a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineJSProfile.js
+++ b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineJSProfile.js
@@ -154,6 +154,8 @@ WebInspector.TimelineJSProfileProcessor.generateJSFrameEvents = function(events)
             depth = jsFramesStack.length;
         }
         var minFrameDurationMs = currentSamplingIntervalMs / 2;
+        for (var k = 0; k < depth; ++k)
+            jsFramesStack[k].setEndTime(time);
         for (var k = depth; k < jsFramesStack.length; ++k)
             jsFramesStack[k].setEndTime(Math.min(eventEndTime(jsFramesStack[k]) + minFrameDurationMs, time));
         jsFramesStack.length = depth;
@@ -178,13 +180,21 @@ WebInspector.TimelineJSProfileProcessor.generateJSFrameEvents = function(events)
      */
     function extractStackTrace(e)
     {
+        var recordTypes = WebInspector.TimelineModel.RecordType;
         var eventData = e.args["data"] || e.args["beginData"];
         var stackTrace = eventData && eventData["stackTrace"];
-        var recordTypes = WebInspector.TimelineModel.RecordType;
-        // GC events do not hold call stack, so make a copy of the current stack.
-        if (e.name === recordTypes.GCEvent || e.name === recordTypes.MajorGC || e.name === recordTypes.MinorGC)
-            stackTrace = jsFramesStack.map(function(frameEvent) { return frameEvent.args["data"]; }).reverse();
-        if (!stackTrace)
+        if (!stackTrace) {
+            stackTrace = jsFramesStack.map(frameEvent => frameEvent.args["data"]).reverse();
+            if (eventData && stackTrace.length)
+                eventData["stackTrace"] = stackTrace;
+        }
+        // FIXME(alph): Sometimes there is an extra stack frame with anonymous function on top. Remove it.
+        if (stackTrace.length) {
+            var topFrame = stackTrace[0];
+            if (topFrame.functionName === "" && topFrame.url === "")
+                stackTrace.splice(0, 1);

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

stackTrace.shift()? Also, consider moving into the conditional above and doing
before reverse(), so you can pop() instead.

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

Acknowledged.

+        }
+        if (!stackTrace.length)
             return;
         if (filterNativeFunctions)
             filterStackFrames(stackTrace);