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

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 WebInspector.TimelineJSProfileProcessor = { };
 
 /**
  * @param {!ProfilerAgent.CPUProfile} jsProfile
  * @param {!WebInspector.TracingModel.Thread} thread
@@ skipping 136 matching lines @@
             if (depth < lockedDepth) {
                 console.error("Child stack is shallower (" + depth + ") than the parent stack (" + lockedDepth + ") at " + time);
                 depth = lockedDepth;
             }
         }
         if (jsFramesStack.length < depth) {
             console.error("Trying to truncate higher than the current stack size at " + time);
             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;
     }
 
     /**
      * @param {!Array<!ConsoleAgent.CallFrame>} stack
      */
     function filterStackFrames(stack)
     {
         for (var i = 0, j = 0; i < stack.length; ++i) {
             var url = stack[i].url;
             if (url && url.startsWith("native "))
                 continue;
             stack[j++] = stack[i];
         }
         stack.length = j;
     }
 
     /**
      * @param {!WebInspector.TracingModel.Event} e
      */
     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);
         var endTime = eventEndTime(e);
         var numFrames = stackTrace.length;
         var minFrames = Math.min(numFrames, jsFramesStack.length);
         var i;
         for (i = lockedJsStackDepth.peekLast() || 0; i < minFrames; ++i) {
             var newFrame = stackTrace[numFrames - 1 - i];
             var oldFrame = jsFramesStack[i].args["data"];
@@ skipping 307 matching lines @@
                 WebInspector.TracingModel.Phase.Instant, e.startTime, e.thread);
             sampleEvent.ordinal = e.ordinal;
             sampleEvent.args = {"data": {"stackTrace": stack }};
             samples.push(sampleEvent);
             break;
         }
     }
 
     return samples;
 }