Use a weak pointer when binding GuestViewBase::DidAttach.

components/guest_view/browser/guest_view_message_filter.cc

 // 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.
 
 #include "components/guest_view/browser/guest_view_message_filter.h"
 
 #include "base/memory/ptr_util.h"
 #include "components/guest_view/browser/guest_view_base.h"
 #include "components/guest_view/browser/guest_view_manager.h"
 #include "components/guest_view/browser/guest_view_manager_delegate.h"
@@ skipping 126 matching lines @@
   // This sets up the embedder and guest pairing information inside
   // the manager.
   manager->AttachGuest(render_process_id_, element_instance_id,
                        guest_instance_id, params);
 
   owner_web_contents->GetMainFrame()->Send(
       new GuestViewMsg_AttachToEmbedderFrame_ACK(element_instance_id));
 
   guest->WillAttach(
       owner_web_contents, element_instance_id, false,
-      base::Bind(&GuestViewMessageFilter::WillAttachCallback, this, guest));
+      base::Bind(&GuestViewBase::DidAttach,
+                 guest->weak_ptr_factory_.GetWeakPtr(), MSG_ROUTING_NONE));
 
   // Attach this inner WebContents |guest_web_contents| to the outer
   // WebContents |owner_web_contents|. The outer WebContents's
   // frame |embedder_frame| hosts the inner WebContents.
   // NOTE: this must be called last, because it could unblock pending requests
   // which depend on the WebViewGuest being initialized which happens above.
   guest_web_contents->AttachToOuterWebContentsFrame(owner_web_contents,
                                                     embedder_frame);
 }
 
-void GuestViewMessageFilter::WillAttachCallback(GuestViewBase* guest) {
-  guest->DidAttach(MSG_ROUTING_NONE);
-}
-
 }  // namespace guest_view