<webview>: Speculative crash fix

chrome/browser/guestview/guestview.h

 // Copyright 2013 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 CHROME_BROWSER_GUESTVIEW_GUESTVIEW_H_
 #define CHROME_BROWSER_GUESTVIEW_GUESTVIEW_H_
 
 #include <queue>
 
+#include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "content/public/browser/browser_plugin_guest_delegate.h"
 #include "content/public/browser/web_contents.h"
 
 class AdViewGuest;
 class WebViewGuest;
 struct RendererContentSettingRules;
 
 // A GuestView is the base class browser-side API implementation for a <*view>
 // tag. GuestView maintains an association between a guest WebContents and an
@@ skipping 105 matching lines @@
   // WebContents.
   const int guest_instance_id_;
   // |view_instance_id_| is an identifier that's unique within a particular
   // embedder RenderViewHost for a particular <*view> instance.
   int view_instance_id_;
 
   // This is a queue of Events that are destined to be sent to the embedder once
   // the guest is attached to a particular embedder.
   std::queue<Event*> pending_events_;
 
+  // This is used to ensure pending tasks will not fire after this object is
+  // destroyed.
+  base::WeakPtrFactory<GuestView> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(GuestView);
 };
 
 #endif  // CHROME_BROWSER_GUESTVIEW_GUESTVIEW_H_