DevTools: add Tracing agent on back-end

Source/devtools/front_end/sdk/TracingModel.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.
  */
 
 /**
  * @constructor
  * @extends {WebInspector.Object}
  */
@@ skipping 47 matching lines @@
     DeleteObject: "D"
 };
 
 WebInspector.TracingModel.MetadataEvent = {
     ProcessSortIndex: "process_sort_index",
     ProcessName: "process_name",
     ThreadSortIndex: "thread_sort_index",
     ThreadName: "thread_name"
 }
 
+WebInspector.TracingModel.DevToolsMetadataEventCategory = "disabled-by-default-devtools.timeline";
+
+WebInspector.TracingModel.DevToolsMetadataEvent = {
+    TracingStartedInPage: "TracingStartedInPage",
+    SetLayerTreeId: "SetLayerTreeId"
+};
+
 WebInspector.TracingModel.prototype = {
     /**
-     * @param {string} categoryPatterns
+     * @param {string} categoryFilter
+     */
+    enable: function(categoryFilter)
+    {
+        TracingAgent.enable(categoryFilter);
+    },
+
+    /**
+     * @param {string} categoryFilter
      * @param {string} options
      * @param {function(?string)=} callback
      */
-    start: function(categoryPatterns, options, callback)
+    start: function(categoryFilter, options, callback)
     {
         this.reset();
         var bufferUsageReportingIntervalMs = 500;
-        TracingAgent.start(categoryPatterns, options, bufferUsageReportingIntervalMs, callback);
+        /**
+         * @param {?string} error
+         * @param {string} sessionId
+         * @this {WebInspector.TracingModel}
+         */
+        function callbackWrapper(error, sessionId)
+        {
+            this._sessionId = sessionId;
+            callback(error);
+        }
+        TracingAgent.start(categoryFilter, options, bufferUsageReportingIntervalMs, callbackWrapper.bind(this));
         this._active = true;
+        this._sessionId = null;
     },
 
     /**
      * @param {function()} callback
      */
     stop: function(callback)
     {
         if (!this._active) {
             callback();
             return;
         }
         this._pendingStopCallback = callback;
         TracingAgent.end();
     },
 
     /**
+     * @return {?string}
+     */
+    sessionId: function()
+    {
+        return this._sessionId;
+    },
+
+    /**
      * @param {number} usage
      */
     _bufferUsage: function(usage)
     {
         this.dispatchEventToListeners(WebInspector.TracingModel.Events.BufferUsage, usage);
     },
 
     /**
      * @param {!Array.<!WebInspector.TracingModel.EventPayload>} events
      */
@@ skipping 320 matching lines @@
  * @constructor
  * @implements {TracingAgent.Dispatcher}
  * @param {!WebInspector.TracingModel} tracingModel
  */
 WebInspector.TracingDispatcher = function(tracingModel)
 {
     this._tracingModel = tracingModel;
 }
 
 WebInspector.TracingDispatcher.prototype = {
+    /**
+     * @param {number} usage
+     */
     bufferUsage: function(usage)
     {
         this._tracingModel._bufferUsage(usage);
     },
 
+    /**
+     * @param {!Array.<!WebInspector.TracingModel.EventPayload>} data
+     */
     dataCollected: function(data)
     {
         this._tracingModel._eventsCollected(data);
     },
 
     tracingComplete: function()
     {
         this._tracingModel._tracingComplete();
     }
 }