Fix for 'Simple Adblock' extension crashes

content/renderer/render_widget.h

 // Copyright (c) 2012 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 CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 333 matching lines @@
       ExternalPopupMenu* popup, ScreenMetricsEmulator* emulator);
 #endif
 
   // RenderWidget IPC message handlers
   void OnHandleInputEvent(const blink::WebInputEvent* event,
                           const ui::LatencyInfo& latency_info,
                           bool keyboard_shortcut);
   void OnCursorVisibilityChange(bool is_visible);
   void OnMouseCaptureLost();
   virtual void OnSetFocus(bool enable);
-  void OnClose();
+  virtual void OnClose();
   void OnCreatingNewAck();
   virtual void OnResize(const ViewMsg_Resize_Params& params);
   void OnChangeResizeRect(const gfx::Rect& resizer_rect);
   virtual void OnWasHidden();
   virtual void OnWasShown(bool needs_repainting);
   virtual void OnWasSwappedOut();
   void OnCreateVideoAck(int32 video_id);
   void OnUpdateVideoAck(int32 video_id);
   void OnRequestMoveAck();
   void OnSetInputMethodActive(bool is_active);
@@ skipping 356 matching lines @@
 
   ui::MenuSourceType context_menu_source_type_;
   gfx::Point touch_editing_context_menu_location_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_