app_list: Fix shadow bleeds over launcher button and steals mouse events

ui/app_list/app_list_bubble_border.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 UI_APP_LIST_APP_LIST_BUBBLE_BORDER_H_
 #define UI_APP_LIST_APP_LIST_BUBBLE_BORDER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "ui/gfx/shadow_value.h"
 #include "ui/views/bubble/bubble_border.h"
 
 namespace app_list {
 
 // A class to paint bubble border and background.
 class AppListBubbleBorder : public views::BubbleBorder {
  public:
   AppListBubbleBorder(views::View* app_list_view,
                       views::View* search_box_view);
   virtual ~AppListBubbleBorder();
 
   bool ArrowAtTopOrBottom() const;
   bool ArrowOnLeftOrRight() const;
 
+  void GetMask(const gfx::Rect& bounds, gfx::Path* mask) const;
+
   void set_offset(const gfx::Point& offset) { offset_ = offset; }
   const gfx::Point& offset() const { return offset_; }
 
  private:
   // Gets arrow offset based on arrow location and |offset_|.
   int GetArrowOffset() const;
 
   void PaintBackground(gfx::Canvas* canvas,
                        const gfx::Rect& bounds) const;
 
@@ skipping 16 matching lines @@
   gfx::Point offset_;
 
   gfx::ShadowValues shadows_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListBubbleBorder);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_BUBBLE_BORDER_H_