Implement support for <extensionoptions> embedding in WebUI

chrome/browser/guest_view/extension_options/extension_options_guest.cc

 // 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.
 
 #include "chrome/browser/guest_view/extension_options/extension_options_guest.h"
 
 #include "base/values.h"
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/guest_view/extension_options/extension_options_constants.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 46 matching lines @@
     const WebContentsCreatedCallback& callback) {
   // Get the extension's base URL.
   std::string extension_id;
   create_params.GetString(extensionoptions::kExtensionId, &extension_id);
 
   if (!extensions::Extension::IdIsValid(extension_id)) {
     callback.Run(NULL);
     return;
   }
 
-  if (extension_id != embedder_extension_id) {
+  if (extensions::Extension::IdIsValid(embedder_extension_id) &&
+      extension_id != embedder_extension_id) {
+    // Extensions cannot embed other extensions' options pages.
     callback.Run(NULL);
     return;
   }
 
   GURL extension_url =
       extensions::Extension::GetBaseURLFromExtensionId(extension_id);
   if (!extension_url.is_valid()) {
     callback.Run(NULL);
     return;
   }
@@ skipping 90 matching lines @@
   int min_width = 0;
   extra_params()->GetInteger(extensionoptions::kAttributeMinHeight,
                              &min_height);
   extra_params()->GetInteger(extensionoptions::kAttributeMinWidth, &min_width);
 
   // Call SetAutoSize to apply all the appropriate validation and clipping of
   // values.
   SetAutoSize(
       true, gfx::Size(min_width, min_height), gfx::Size(max_width, max_height));
 }