Fix webrequest api for webview in webui

extensions/browser/guest_view/web_view/web_view_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 "extensions/browser/guest_view/web_view/web_view_guest.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/browser_context.h"
@@ skipping 331 matching lines @@
     web_view_guest_delegate_->OnAttachWebViewHelpers(contents);
   web_view_permission_helper_.reset(new WebViewPermissionHelper(this));
 }
 
 void WebViewGuest::DidStopLoading() {
   scoped_ptr<base::DictionaryValue> args(new base::DictionaryValue());
   DispatchEventToEmbedder(
       new GuestViewBase::Event(webview::kEventLoadStop, args.Pass()));
 }
 
+void WebViewGuest::WillDetachFromEmbedder() {
+  if (web_view_guest_delegate_)
+    web_view_guest_delegate_->OnWillDetachFromEmbedder();
+}
+
 void WebViewGuest::EmbedderDestroyed() {
   content::BrowserThread::PostTask(
       content::BrowserThread::IO,
       FROM_HERE,
       base::Bind(
           &RemoveWebViewEventListenersOnIOThread,
           browser_context(),
           embedder_extension_id(),
           embedder_render_process_id(),
           view_instance_id()));
@@ skipping 863 matching lines @@
   WebViewGuest* guest =
       WebViewGuest::From(embedder_render_process_id(), new_window_instance_id);
   if (!guest)
     return;
 
   if (!allow)
     guest->Destroy();
 }
 
 }  // namespace extensions