DevTools: Resume targets *after* stopping timeline recording.

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

Index: third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
diff --git a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
index 853765d809ae17427fce6fd88ee911a0fb84e292..e7a796fe2658d20a3e00509d47abb66ed770b9ff 100644
--- a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
+++ b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineController.js
@@ -70,10 +70,11 @@ WebInspector.TimelineController.prototype = {
 
     stopRecording: function()
     {
-        WebInspector.targetManager.resumeAllTargets();
         this._allProfilesStoppedPromise = this._stopProfilingOnAllTargets();
-        if (this._targets[0])
-            this._targets[0].tracingManager.stop();
+        var mainTarget = WebInspector.targetManager.mainTarget();
+        if (mainTarget)
+            mainTarget.tracingManager.stop();
+        WebInspector.targetManager.resumeAllTargets();
         this._delegate.loadingStarted();
     },
 
@@ -97,6 +98,8 @@ WebInspector.TimelineController.prototype = {
         this._targets.remove(target, true);
         // FIXME: We'd like to stop profiling on the target and retrieve a profile
         // but it's too late. Backend connection is closed.
+        if (this._profiling)
+            WebInspector.console.log(WebInspector.UIString("A target is disconnected while profiling. Its profile will not be retrieved."));

[pfeldman, 2016/03/17 00:34:31]

Don't output this message - it jumps at the user in the middle of the recording.
Surface it upon stop instead.

"One of the targets (worker?) was disconnected while profiling. Its profile was
not captured."

[alph, 2016/03/17 01:10:08]

Done.

     },
 
     /**
@@ -114,7 +117,9 @@ WebInspector.TimelineController.prototype = {
     _startProfilingOnAllTargets: function()
     {
         var intervalUs = WebInspector.moduleSetting("highResolutionCpuProfiling").get() ? 100 : 1000;
-        this._targets[0].profilerAgent().setSamplingInterval(intervalUs);
+        var mainTarget = WebInspector.targetManager.mainTarget();
+        if (mainTarget)
+            mainTarget.profilerAgent().setSamplingInterval(intervalUs);
         this._profiling = true;
         return Promise.all(this._targets.map(this._startProfilingOnTarget));
     },
@@ -125,16 +130,8 @@ WebInspector.TimelineController.prototype = {
      */
     _stopProfilingOnTarget: function(target)
     {
-        /**
-         * @param {?Protocol.Error} error
-         * @param {?ProfilerAgent.CPUProfile} profile
-         * @return {?ProfilerAgent.CPUProfile}
-         */
-        function extractProfile(error, profile)
-        {
-            return !error && profile ? profile : null;
-        }
-        return target.profilerAgent().stop(extractProfile).then(this._addCpuProfile.bind(this, target.id()));
+        return target.profilerAgent().stop((error, profile) => !error && profile ? profile : null)
+            .then(this._addCpuProfile.bind(this, target.id()));
     },
 
     /**
@@ -161,7 +158,7 @@ WebInspector.TimelineController.prototype = {
             this._startProfilingOnAllTargets() : Promise.resolve();
         var samplingFrequencyHz = WebInspector.moduleSetting("highResolutionCpuProfiling").get() ? 10000 : 1000;
         var options = "sampling-frequency=" + samplingFrequencyHz;
-        var mainTarget = this._targets[0];
+        var mainTarget = WebInspector.targetManager.mainTarget();
         var tracingManager = mainTarget.tracingManager;
         mainTarget.resourceTreeModel.suspendReload();
         profilingStartedPromise.then(tracingManager.start.bind(tracingManager, this, categories, options, onTraceStarted));
@@ -247,7 +244,7 @@ WebInspector.TimelineController.prototype = {
             return;
 
         var pid = mainMetaEvent.thread.process().id();
-        var mainTarget = this._targets[0];
+        var mainTarget = WebInspector.targetManager.mainTarget();
         var mainCpuProfile = this._cpuProfiles.get(mainTarget.id());
         this._injectCpuProfileEvent(pid, mainMetaEvent.thread.id(), mainCpuProfile);