Adds a porting layer so aura can be made to work with mus

ui/aura/window_tree_host.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_TREE_HOST_H_
 #define UI_AURA_WINDOW_TREE_HOST_H_
 
+#include <memory>
 #include <vector>
 
 #include "base/event_types.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "ui/aura/aura_export.h"
 #include "ui/base/cursor/cursor.h"
 #include "ui/base/ime/input_method_delegate.h"
 #include "ui/events/event_source.h"
 #include "ui/gfx/geometry/insets.h"
@@ skipping 14 matching lines @@
 class InputMethod;
 class ViewProp;
 }
 
 namespace aura {
 namespace test {
 class WindowTreeHostTestApi;
 }
 
 class WindowEventDispatcher;
+class WindowPort;
 class WindowTreeHostObserver;
 
 // WindowTreeHost bridges between a native window and the embedded RootWindow.
 // It provides the accelerated widget and maps events from the native os to
 // aura.
 class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
                                    public ui::EventSource {
  public:
   ~WindowTreeHost() override;
 
@@ skipping 125 matching lines @@
   // Sets the OS capture to the root window.
   virtual void SetCapture() = 0;
 
   // Releases OS capture of the root window.
   virtual void ReleaseCapture() = 0;
 
  protected:
   friend class TestScreen;  // TODO(beng): see if we can remove/consolidate.
 
   WindowTreeHost();
+  explicit WindowTreeHost(std::unique_ptr<WindowPort> window_port);
+
   void DestroyCompositor();
   void DestroyDispatcher();
 
   void CreateCompositor();
   void OnAcceleratedWidgetAvailable();
 
   // Returns the location of the RootWindow on native screen.
   virtual gfx::Point GetLocationOnNativeScreen() const = 0;
 
   void OnHostMoved(const gfx::Point& new_location);
@@ skipping 58 matching lines @@
   bool owned_input_method_;
 
   gfx::Insets output_surface_padding_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHost);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_TREE_HOST_H_