[Extensions] Don't allow built-in extensions code to be overridden

extensions/renderer/resources/last_error.js

 // Copyright 2014 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.
 
 var GetAvailability = requireNative('v8_context').GetAvailability;
 var GetGlobal = requireNative('sendRequest').GetGlobal;
 
 // Utility for setting chrome.*.lastError.
 //
 // A utility here is useful for two reasons:
@@ skipping 116 matching lines @@
  * @param {string=} stack - Stack trace of the call up to the error.
  */
 function reportIfUnchecked(name, targetChrome, stack) {
   if (hasAccessed(targetChrome) || !hasError(targetChrome))
     return;
   var message = targetChrome.runtime.lastError.message;
   console.error("Unchecked runtime.lastError while running " +
       (name || "unknown") + ": " + message + (stack ? "\n" + stack : ""));
 }
 
-exports.clear = clear;
-exports.hasAccessed = hasAccessed;
-exports.hasError = hasError;
-exports.set = set;
-exports.run = run;
-exports.reportIfUnchecked = reportIfUnchecked;
+exports.$set('clear', clear);

[Devlin, 2015/10/23 22:08:28]

Once we decide what's best here, this'll need to be done on all exports.

+exports.$set('hasAccessed', hasAccessed);
+exports.$set('hasError', hasError);
+exports.$set('set', set);
+exports.$set('run', run);
+exports.$set('reportIfUnchecked', reportIfUnchecked);