DevTools: add extension API to contribute trace events to timeline

third_party/WebKit/Source/devtools/front_end/timeline/TimelineLoader.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.
 /**
  * @implements {Common.OutputStream}
  * @implements {Bindings.OutputStreamDelegate}
  * @unrestricted
  */
 Timeline.TimelineLoader = class {
   /**
    * @param {!SDK.TracingModel} model
-   * @param {!Timeline.TimelineLifecycleDelegate} delegate
+   * @param {!Timeline.LoaderClient} delegate
    */
   constructor(model, delegate) {
     this._model = model;
     this._delegate = delegate;
 
     /** @type {?function()} */
     this._canceledCallback = null;
 
     this._state = Timeline.TimelineLoader.State.Initial;
     this._buffer = '';
@@ skipping 16 matching lines @@
     var fileReader = Timeline.TimelineLoader._createFileReader(file, loader);
     loader._canceledCallback = fileReader.cancel.bind(fileReader);
     loader._totalSize = file.size;
     fileReader.start(loader);
     return loader;
   }
 
   /**
    * @param {!SDK.TracingModel} model
    * @param {string} url
-   * @param {!Timeline.TimelineLifecycleDelegate} delegate
+   * @param {!Timeline.LoaderClient} delegate
    * @return {!Timeline.TimelineLoader}
    */
   static loadFromURL(model, url, delegate) {
     var stream = new Timeline.TimelineLoader(model, delegate);
     Host.ResourceLoader.loadAsStream(url, null, stream);
     return stream;
   }
 
   /**
    * @param {!File} file
@@ skipping 205 matching lines @@
    * @override
    * @param {!Bindings.ChunkedReader} reader
    * @param {!Event} event
    */
   onError(reader, event) {
     var error = event.target.error;
     Common.console.error(
         Common.UIString('Failed to save timeline: %s (%s, %s)', error.message, error.name, error.code));
   }
 };