DevTools: add an API for extension-supplied trace providers

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}
@@ skipping 11 matching lines @@
 WebInspector.TimelineController.prototype = {
     /**
      * @param {boolean} captureCauses
      * @param {boolean} enableJSSampling
      * @param {boolean} captureMemory
      * @param {boolean} capturePictures
      * @param {boolean} captureFilmStrip
      */
     startRecording: function(captureCauses, enableJSSampling, captureMemory, capturePictures, captureFilmStrip)
     {
+        this._extensionTraceProviders = WebInspector.extensionServer.traceProviders().slice();
+
         function disabledByDefault(category)
         {
             return "disabled-by-default-" + category;
         }
         var categoriesArray = [
             "-*",
             "devtools.timeline",
             "v8.execute",
             disabledByDefault("devtools.timeline"),
             disabledByDefault("devtools.timeline.frame"),
@@ skipping 17 matching lines @@
         if (captureCauses && Runtime.experiments.isEnabled("timelineInvalidationTracking"))
             categoriesArray.push(disabledByDefault("devtools.timeline.invalidationTracking"));
         if (capturePictures) {
             categoriesArray.push(disabledByDefault("devtools.timeline.layers"),
                                  disabledByDefault("devtools.timeline.picture"),
                                  disabledByDefault("blink.graphics_context_annotations"));
         }
         if (captureFilmStrip)
             categoriesArray.push(disabledByDefault("devtools.screenshot"));
 
+        for (var traceProvider of this._extensionTraceProviders)
+            traceProvider.start();
+
         var categories = categoriesArray.join(",");
         this._startRecordingWithCategories(categories, enableJSSampling);
     },
 
     stopRecording: function()
     {
         var tracingStoppedPromises = [];
         tracingStoppedPromises.push(new Promise(resolve => this._tracingCompleteCallback = resolve));
         tracingStoppedPromises.push(this._stopProfilingOnAllTargets());
         this._target.tracingManager.stop();
         tracingStoppedPromises.push(WebInspector.targetManager.resumeAllTargets());
         Promise.all(tracingStoppedPromises).then(() => this._allSourcesFinished());
 
         this._delegate.loadingStarted();
+
+        for (var traceProvider of this._extensionTraceProviders)
+            traceProvider.stop();
     },
 
     /**
      * @override
      * @param {!WebInspector.Target} target
      */
     targetAdded: function(target)
     {
         this._targets.push(target);
         if (this._profiling)
@@ skipping 186 matching lines @@
 
     /**
      * @param {number} progress
      * @override
      */
     eventsRetrievalProgress: function(progress)
     {
         this._delegate.loadingProgress(progress);
     }
 }