Fix webrequest api for webview in webui

chrome/browser/guest_view/web_view/chrome_web_view_guest_delegate.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/web_view/chrome_web_view_guest_delegate.h"
 
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/favicon/favicon_tab_helper.h"
 #include "chrome/browser/renderer_context_menu/render_view_context_menu.h"
@@ skipping 124 matching lines @@
     InjectChromeVoxIfNeeded(render_frame_host->GetRenderViewHost());
 }
 
 void ChromeWebViewGuestDelegate::OnGuestReady() {
   ZoomController* zoom_controller =
       ZoomController::FromWebContents(guest_web_contents());
   DCHECK(zoom_controller);
   zoom_controller->SetZoomMode(ZoomController::ZOOM_MODE_ISOLATED);
 }
 
+void ChromeWebViewGuestDelegate::OnEmbedderWillBeDestroyed() {
+  content::WebContents* embedder_web_contents =
+      web_view_guest()->embedder_web_contents();
+  if (!embedder_web_contents)
+    return;
+
+  ZoomController* zoom_controller =
+      ZoomController::FromWebContents(embedder_web_contents);
+  if (zoom_controller)
+    zoom_controller->RemoveObserver(this);
+}
+
 void ChromeWebViewGuestDelegate::OnGuestDestroyed() {
   // Clean up custom context menu items for this guest.
   extensions::MenuManager* menu_manager = extensions::MenuManager::Get(
       Profile::FromBrowserContext(web_view_guest()->browser_context()));
   menu_manager->RemoveAllContextItems(extensions::MenuItem::ExtensionKey(
       web_view_guest()->embedder_extension_id(),
       web_view_guest()->view_instance_id()));
 }
 
 // static
@@ skipping 73 matching lines @@
       chromevox_injected_ = false;
   }
 }
 #endif
 
 void ChromeWebViewGuestDelegate::OnZoomChanged(
     const ZoomController::ZoomChangedEventData& data) {
   ZoomController::FromWebContents(guest_web_contents())->
       SetZoomLevel(data.new_zoom_level);
 }