Merge 101221 - Reland 101111 - Only deliver extension messages to contexts that care.

chrome/renderer/resources/renderer_extension_bindings.js

 // Copyright (c) 2011 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.
 
 // This script contains unprivileged javascript APIs related to chrome
 // extensions.  It is loaded by any extension-related context, such as content
 // scripts or toolstrips.
 // See user_script_slave.cc for script that is loaded by content scripts only.
 // TODO(mpcomplete): we also load this in regular web pages, but don't need to.
 
@@ skipping 28 matching lines @@
   // which messages can be passed.
   chrome.Port = function(portId, opt_name) {
     this.portId_ = portId;
     this.name = opt_name;
     this.onDisconnect = new chrome.Event();
     this.onMessage = new chrome.Event();
   };
 
   chromeHidden.Port = {};
 
+  // Returns true if the specified port id is in this context. This is used by
+  // the C++ to avoid creating the javascript message for all the contexts that
+  // don't care about a particular message.
+  chromeHidden.Port.hasPort = function(portId) {
+    return portId in ports;
+  };
+
   // Hidden port creation function.  We don't want to expose an API that lets
   // people add arbitrary port IDs to the port list.
   chromeHidden.Port.createPort = function(portId, opt_name) {
     if (ports[portId]) {
       throw new Error("Port '" + portId + "' already exists.");
     }
     var port = new chrome.Port(portId, opt_name);
     ports[portId] = port;
     portReleasers[portId] = PortRelease.bind(this, portId);
     chromeHidden.onUnload.addListener(portReleasers[portId]);
@@ skipping 294 matching lines @@
       "extension.onRequestExternal",
       "extension.setUpdateUrlData",
       "i18n.getAcceptLanguages"
     ];
     for (var i = 0; i < privileged.length; i++) {
       createStub(privileged[i]);
     }
   }
 
 })();