Prevent extensions from clobbering JSON implementation that extension calls use

chrome/renderer/resources/renderer_extension_bindings.js

 // Copyright (c) 2009 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 57 matching lines @@
     if (targetExtensionId != chromeHidden.extensionId)
       return;  // not for us
     if (ports[getOppositePortId(portId)])
       return;  // this channel was opened by us, so ignore it
 
     // Determine whether this is coming from another extension, so we can use
     // the right event.
     var isExternal = sourceExtensionId != chromeHidden.extensionId;
 
     if (tab)
-      tab = JSON.parse(tab);
+      tab = chromeHidden.JSON.parse(tab);
     var sender = {tab: tab, id: sourceExtensionId};
 
     // Special case for sendRequest/onRequest.
     if (channelName == chromeHidden.kRequestChannel) {
       var requestEvent = (isExternal ?
           chrome.extension.onRequestExternal : chrome.extension.onRequest);
       if (requestEvent.hasListeners()) {
         var port = chromeHidden.Port.createPort(portId, channelName);
         port.onMessage.addListener(function(request) {
           requestEvent.dispatch(request, sender, function(response) {
@@ skipping 23 matching lines @@
       port.onDisconnect.dispatch(port);
       delete ports[portId];
     }
   };
 
   // Called by native code when a message has been sent to the given port.
   chromeHidden.Port.dispatchOnMessage = function(msg, portId) {
     var port = ports[portId];
     if (port) {
       if (msg) {
-        msg = JSON.parse(msg);
+        msg = chromeHidden.JSON.parse(msg);
       }
       port.onMessage.dispatch(msg, port);
     }
   };
 
   // Sends a message asynchronously to the context on the other end of this
   // port.
   chrome.Port.prototype.postMessage = function(msg) {
     // JSON.stringify doesn't support a root object which is undefined.
     if (msg === undefined)
       msg = null;
-    PostMessage(this.portId_, JSON.stringify(msg));
+    PostMessage(this.portId_, chromeHidden.JSON.stringify(msg));
   };
 
   // Disconnects the port from the other end.
   chrome.Port.prototype.disconnect = function() {
     delete ports[this.portId_];
     CloseChannel(this.portId_);
   }
 
   // This function is called on context initialization for both content scripts
   // and extension contexts.
@@ skipping 128 matching lines @@
       "extension.onConnectExternal",
       "extension.onRequestExternal",
       "i18n.getAcceptLanguages"
     ];
     for (var i = 0; i < privileged.length; i++) {
       createStub(privileged[i]);
     }
   }
 
 })();