<webview>: Speculative crash fix

chrome/browser/guestview/guestview.h

Index: chrome/browser/guestview/guestview.h
diff --git a/chrome/browser/guestview/guestview.h b/chrome/browser/guestview/guestview.h
index 46485840a62a5b616aa07ee4e700bc82360060c2..368e94a66babbfd9b6e65e934d944f834b96b30c 100644
--- a/chrome/browser/guestview/guestview.h
+++ b/chrome/browser/guestview/guestview.h
@@ -7,6 +7,7 @@
 
 #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"
@@ -132,6 +133,10 @@ class GuestView : public content::BrowserPluginGuestDelegate {
   // 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);
 };