DevTools: Introduce Target class which holds connection & models

Source/devtools/front_end/InspectorBackend.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 320 matching lines @@
     /**
      * @param {string} domain
      * @return {!InspectorBackendClass.AgentPrototype}
      */
     agent: function(domain)
     {
         return this._agents[domain];
     },
 
     /**
+     * @return {!Array.<string>}
+     */
+    domains: function()
+    {
+        return Object.keys(this._agents);
+    },
+
+    /**
      * @param {string} domain
      * @param {string} method
      * @param {?Object} params
      * @param {?function(*)} callback
      * @private
      */
     _wrapCallbackAndSendMessageObject: function(domain, method, params, callback)
     {
         var messageObject = {};
         messageObject.method = method;
@@ skipping 356 matching lines @@
     }
 
 }
 
 InspectorBackendClass.Options = {
     dumpInspectorTimeStats: false,
     dumpInspectorProtocolMessages: false
 }
 
 InspectorBackend = new InspectorBackendClass();