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

ui/aura/mus/window_port_mus.h

 // Copyright 2016 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_MUS_WINDOW_PORT_MUS_H_
 #define UI_AURA_MUS_WINDOW_PORT_MUS_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 40 matching lines @@
  public:
   // See WindowMus's constructor for details on |window_mus_type|.
   WindowPortMus(WindowTreeClient* client, WindowMusType window_mus_type);
   ~WindowPortMus() override;
 
   static WindowPortMus* Get(Window* window);
 
   Window* window() { return window_; }
   const Window* window() const { return window_; }
 
+  cc::FrameSinkId frame_sink_id() const { return frame_sink_id_; }
+
   ClientSurfaceEmbedder* client_surface_embedder() const {
     return client_surface_embedder_.get();
   }
 
   const cc::SurfaceInfo& PrimarySurfaceInfoForTesting() const {
     return primary_surface_info_;
   }
 
   void SetTextInputState(mojo::TextInputStatePtr state);
   void SetImeVisibility(bool visible, mojo::TextInputStatePtr state);
@@ skipping 20 matching lines @@
 
   std::unique_ptr<viz::ClientLayerTreeFrameSink> RequestLayerTreeFrameSink(
       scoped_refptr<cc::ContextProvider> context_provider,
       gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager);
 
  private:
   friend class WindowPortMusTestApi;
   friend class WindowTreeClient;
   friend class WindowTreeClientPrivate;
   friend class WindowTreeHostMus;
+  friend class HitTestDataProviderMusTest;
 
   using ServerChangeIdType = uint8_t;
 
   // Changes to the underlying Window originating from the server must be done
   // in such a way that the same change is not applied back to the server. To
   // accomplish this every changes from the server is associated with at least
   // one ServerChange. If the underlying Window ends up calling back to this
   // class and the change is expected then the change is ignored and not sent to
   // the server. For example, here's the flow when the server changes the
   // bounds:
@@ skipping 191 matching lines @@
   // for a local aura::Window, we need keep a weak ptr of it, so we can update
   // the local surface id when necessary.
   base::WeakPtr<viz::ClientLayerTreeFrameSink> local_layer_tree_frame_sink_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowPortMus);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_WINDOW_PORT_MUS_H_