Use a weak pointer when binding GuestViewBase::DidAttach.

components/guest_view/browser/guest_view_message_filter.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_GUEST_VIEW_BROWSER_GUEST_VIEW_MESSAGE_FILTER_H_
 #define COMPONENTS_GUEST_VIEW_BROWSER_GUEST_VIEW_MESSAGE_FILTER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/browser_message_filter.h"
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace content {
 class BrowserContext;
 }
 
 namespace guest_view {
-class GuestViewBase;
 class GuestViewManager;
 
 // This class filters out incoming GuestView-specific IPC messages from the
 // renderer process. It is created on the UI thread. Messages may be handled on
 // the IO thread or the UI thread.
 class GuestViewMessageFilter : public content::BrowserMessageFilter {
  public:
   GuestViewMessageFilter(int render_process_id,
                          content::BrowserContext* context);
 
@@ skipping 31 matching lines @@
   void OnAttachGuest(int element_instance_id,
                      int guest_instance_id,
                      const base::DictionaryValue& attach_params);
   void OnAttachToEmbedderFrame(int embedder_local_render_frame_id,
                                int element_instance_id,
                                int guest_instance_id,
                                const base::DictionaryValue& params);
   void OnViewCreated(int view_instance_id, const std::string& view_type);
   void OnViewGarbageCollected(int view_instance_id);
 
-  void WillAttachCallback(GuestViewBase* guest);
-
   DISALLOW_COPY_AND_ASSIGN(GuestViewMessageFilter);
 };
 
 }  // namespace guest_view
 
 #endif  // COMPONENTS_GUEST_VIEW_BROWSER_GUEST_VIEW_MESSAGE_FILTER_H_