DevTools: use target-based model accessors only.

Source/devtools/front_end/sdk/ResourceTreeModel.js

 /*
  * Copyright (C) 2011 Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 58 matching lines @@
     WillReloadPage: "WillReloadPage",
     InspectedURLChanged: "InspectedURLChanged",
     SecurityOriginAdded: "SecurityOriginAdded",
     SecurityOriginRemoved: "SecurityOriginRemoved",
     ScreencastFrame: "ScreencastFrame",
     ScreencastVisibilityChanged: "ScreencastVisibilityChanged",
     ViewportChanged: "ViewportChanged",
     ColorPicked: "ColorPicked"
 }
 
+
+/**
+ * @return {!Array.<!WebInspector.ResourceTreeFrame>}
+ */
+WebInspector.ResourceTreeModel.frames = function()
+{
+    var result = [];
+    for (var target of WebInspector.targetManager.targets())
+        result = result.concat(Object.values(target.resourceTreeModel._frames));
+    return result;
+}
+
+/**
+ * @param {string} url
+ * @return {?WebInspector.Resource}
+ */
+WebInspector.ResourceTreeModel.resourceForURL = function(url)
+{
+    for (var target of WebInspector.targetManager.targets()) {
+        var mainFrame = target.resourceTreeModel.mainFrame;
+        var result = mainFrame ? mainFrame.resourceForURL(url) : null;
+        if (result)
+            return result;
+    }
+    return null;
+}
+
 WebInspector.ResourceTreeModel.prototype = {
     _fetchResourceTree: function()
     {
         /** @type {!Object.<string, !WebInspector.ResourceTreeFrame>} */
         this._frames = {};
         delete this._cachedResourcesProcessed;
         this._agent.getResourceTree(this._processCachedResources.bind(this));
     },
 
     _processCachedResources: function(error, mainFramePayload)
@@ skipping 813 matching lines @@
     },
 
     /**
      * @override
      */
     interstitialHidden: function()
     {
         // Frontend is not interested in interstitials.
     }
 }
-
-/**
- * @type {!WebInspector.ResourceTreeModel}
- */
-WebInspector.resourceTreeModel;