[mus+ash] Implements hit-test client in Aura

ui/aura/window.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_H_
 #define UI_AURA_WINDOW_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 309 matching lines @@
   // use from the destructor.
   void RemoveOrDestroyChildren();
 
   // Overrides from ui::PropertyHandler
   std::unique_ptr<ui::PropertyData> BeforePropertyChange(const void* key)
       override;
   void AfterPropertyChange(const void* key,
                            int64_t old_value,
                            std::unique_ptr<ui::PropertyData> data) override;
  private:
+  friend class HitTestDataProviderMus;
   friend class LayoutManager;
   friend class PropertyConverter;
   friend class WindowPort;
   friend class WindowPortForShutdown;
   friend class WindowTargeter;
   friend class test::WindowTestApi;
 
   // Returns true if the mouse pointer at relative-to-this-Window's-origin
   // |local_point| can trigger an event for this Window.
   // TODO(beng): A Window can supply a hit-test mask to cause some portions of
@@ skipping 143 matching lines @@
   bool ignore_events_;
 
   base::ObserverList<WindowObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_