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

ui/aura/window_delegate.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_AURA_WINDOW_DELEGATE_H_
 #define UI_AURA_WINDOW_DELEGATE_H_
 #pragma once
 
 #include "ui/aura/aura_export.h"
 #include "ui/base/events.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 class Canvas;
+class Path;
 class Point;
 class Rect;
 class Size;
 }
 
 namespace aura {
 
 class Event;
 class GestureEvent;
 class KeyEvent;
@@ skipping 52 matching lines @@
   // deleted and the window has been removed from its parent.
   // The delegate can use this as an opportunity to delete itself if necessary.
   virtual void OnWindowDestroyed() = 0;
 
   // Called when the visibility of a Window changes. See description in
   // WindowObserver::OnWindowDestroyed() for details.
   // TODO: this should be renamed to OnWindowTargetVisibilityChanged() to
   // match when it's sent.
   virtual void OnWindowVisibilityChanged(bool visible) = 0;
 
+  // Called from Window::HitTest to check if the window has a custom hit test
+  // mask. It works similar to the views counterparts. That is, if the function
+  // returns true, GetHitTestMask below will be called to get the mask.
+  // Otherwise, Window will hit-test against its bounds.
+  virtual bool HasHitTestMask() const = 0;
+
+  // Called from Window::HitTest to retrieve hit test mask when HasHitTestMask
+  // above returns true.
+  virtual void GetHitTestMask(gfx::Path* mask) const = 0;
+
  protected:
   virtual ~WindowDelegate() {}
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_DELEGATE_H_