Use WebFrame::setIsolatedWorldSecurityOrigin to allow cross-origin XHRs in content scripts.

chrome/renderer/extensions/extension_dispatcher.cc

 // 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.
 
 #include "chrome/renderer/extensions/extension_dispatcher.h"
 
 #include "base/command_line.h"
 #include "chrome/common/child_process_logging.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension.h"
@@ skipping 135 matching lines @@
     // --enable-experimental-extension-apis changes at runtime, which happens
     // during browser tests. Existing renderers won't know about the change.
     return;
   }
 
   extensions_.Insert(extension);
 }
 
 void ExtensionDispatcher::OnUnloaded(const std::string& id) {
   extensions_.Remove(id);
+  UserScriptSlave::RemoveIsolatedWorld(id);

[Matt Perry, 2011/05/27 22:14:35]

Could you add a comment here explaining that we do this so that it resets the
origin whitelist for this extension, in case it's reloaded?

 }
 
 void ExtensionDispatcher::OnSetScriptingWhitelist(
     const Extension::ScriptingWhitelist& extension_ids) {
   Extension::SetScriptingWhitelist(extension_ids);
 }
 
 bool ExtensionDispatcher::IsExtensionActive(const std::string& extension_id) {
   return active_extension_ids_.find(extension_id) !=
       active_extension_ids_.end();
@@ skipping 98 matching lines @@
   child_process_logging::SetActiveExtensions(active_extensions);
 }
 
 void ExtensionDispatcher::RegisterExtension(v8::Extension* extension,
                                             bool restrict_to_extensions) {
   if (restrict_to_extensions)
     restricted_v8_extensions_.insert(extension->name());
 
   RenderThread::current()->RegisterExtension(extension);
 }