Reland of Timeline: extract and rename TracingModelLoader into a file of its own

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

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 518 matching lines @@
         return true;
     },
 
     /**
      * @param {!File} file
      */
     _loadFromFile: function(file)
     {
         if (this._state !== WebInspector.TimelinePanel.State.Idle)
             return;
-        this._model.loadFromFile(file, this._prepareToLoadTimeline());
+        WebInspector.TimelineLoader.loadFromFile(this._model, file, this._prepareToLoadTimeline());
         this._createFileSelector();
     },
 
     /**
      * @param {string} url
      */
     _loadFromURL: function(url)
     {
         if (this._state !== WebInspector.TimelinePanel.State.Idle)
             return;
-        this._model.loadFromURL(url, this._prepareToLoadTimeline());
+        WebInspector.TimelineLoader.loadFromURL(this._model, url, this._prepareToLoadTimeline());
     },
 
     _refreshViews: function()
     {
         for (var i = 0; i < this._currentViews.length; ++i) {
             var view = this._currentViews[i];
             view.refreshRecords();
         }
         this._updateSelectionDetails();
     },
@@ skipping 1555 matching lines @@
      * @override
      * @param {!WebInspector.Target} target
      */
     targetRemoved: function(target)
     {
         this._targets.remove(target, true);
     },
 
     __proto__: WebInspector.Object.prototype
 }