Timeline: rearrange trace completion logic for better extensibility

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

 // Copyright 2016 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.
 
 /**
  * @constructor
  * @param {!WebInspector.Target} target
  * @param {!WebInspector.TimelineLifecycleDelegate} delegate
  * @param {!WebInspector.TracingModel} tracingModel
  * @implements {WebInspector.TargetManager.Observer}
  * @implements {WebInspector.TracingManagerClient}
  */
 WebInspector.TimelineController = function(target, delegate, tracingModel)
 {
     this._delegate = delegate;
     this._target = target;
     this._tracingModel = tracingModel;
     this._targets = [];
-    this._allProfilesStoppedPromise = Promise.resolve();
-    this._targetsResumedPromise = Promise.resolve();
     WebInspector.targetManager.observeTargets(this);
 }
 
 WebInspector.TimelineController.prototype = {
     /**
      * @param {boolean} captureCauses
      * @param {boolean} enableJSSampling
      * @param {boolean} captureMemory
      * @param {boolean} capturePictures
      * @param {boolean} captureFilmStrip
@@ skipping 35 matching lines @@
         }
         if (captureFilmStrip)
             categoriesArray.push(disabledByDefault("devtools.screenshot"));
 
         var categories = categoriesArray.join(",");
         this._startRecordingWithCategories(categories, enableJSSampling);
     },
 
     stopRecording: function()
     {
-        this._allProfilesStoppedPromise = this._stopProfilingOnAllTargets();
+        var tracingStoppedPromises = [];
+        tracingStoppedPromises.push(new Promise(resolve => this._tracingCompleteCallback = resolve));
+        tracingStoppedPromises.push(this._stopProfilingOnAllTargets());
         this._target.tracingManager.stop();
-        this._targetsResumedPromise = WebInspector.targetManager.resumeAllTargets();
+        tracingStoppedPromises.push(WebInspector.targetManager.resumeAllTargets());
+        Promise.all(tracingStoppedPromises).then(() => this._allSourcesFinished());
+
         this._delegate.loadingStarted();
     },
 
     /**
      * @override
      * @param {!WebInspector.Target} target
      */
     targetAdded: function(target)
     {
         this._targets.push(target);
@@ skipping 110 matching lines @@
     traceEventsCollected: function(events)
     {
         this._tracingModel.addEvents(events);
     },
 
     /**
      * @override
      */
     tracingComplete: function()
     {
-        Promise.all([this._allProfilesStoppedPromise, this._targetsResumedPromise])
-            .then(this._didStopRecordingTraceEvents.bind(this));
+        this._tracingCompleteCallback();
+        this._tracingCompleteCallback = null;
     },
 
-    _didStopRecordingTraceEvents: function()
+    _allSourcesFinished: function()
     {
         this._injectCpuProfileEvents();
         this._tracingModel.tracingComplete();
         this._delegate.loadingComplete(true);
     },
 
     /**
      * @param {number} pid
      * @param {number} tid
      * @param {?ProfilerAgent.CPUProfile} cpuProfile
@@ skipping 52 matching lines @@
 
     /**
      * @param {number} progress
      * @override
      */
     eventsRetrievalProgress: function(progress)
     {
         this._delegate.loadingProgress(progress);
     }
 }