mustash: Implement basic input event routing in renderer

content/renderer/render_widget_mus_connection.h

Index: content/renderer/render_widget_mus_connection.h
diff --git a/content/renderer/render_widget_mus_connection.h b/content/renderer/render_widget_mus_connection.h
index b3f45494b34b5b4e43c035ff54f1f68fad9fb4e3..316fbbc875fe46e4af7d30e83c9a1be010ec04e1 100644
--- a/content/renderer/render_widget_mus_connection.h
+++ b/content/renderer/render_widget_mus_connection.h
@@ -6,44 +6,46 @@
 #define CONTENT_RENDERER_RENDER_WIDGET_MUS_CONNECTION_H_
 
 #include "base/macros.h"
+#include "base/threading/thread_checker.h"
 #include "cc/output/output_surface.h"
-#include "components/mus/public/cpp/window.h"
-#include "components/mus/public/cpp/window_observer.h"
 #include "components/mus/public/cpp/window_surface.h"
-#include "components/mus/public/cpp/window_tree_connection.h"
-#include "components/mus/public/cpp/window_tree_delegate.h"
-#include "mojo/public/cpp/bindings/binding.h"
+#include "content/renderer/compositor_mus_connection.h"
 
 namespace content {
 
-class RenderWidgetMusConnection : public mus::WindowTreeDelegate,
-                                  public mus::WindowObserver {
- public:
-  explicit RenderWidgetMusConnection(int routing_id);
-  ~RenderWidgetMusConnection() override;
+class InputHandlerManager;
 
-  // Connect to a WindowTreeClient request.
+// Use on main thread.
+class RenderWidgetMusConnection {
+ public:
+  // Bind to a WindowTreeClient request.
   void Bind(mojo::InterfaceRequest<mus::mojom::WindowTreeClient> request);
 
   // Create a cc output surface.
   scoped_ptr<cc::OutputSurface> CreateOutputSurface();
 
+  static RenderWidgetMusConnection* Get(int routing_id);
+
   // Get the connection from a routing_id, if the connection doesn't exist,
   // a new connection will be created.
   static RenderWidgetMusConnection* GetOrCreate(int routing_id);
 
  private:
-  // WindowTreeDelegate implementation:
-  void OnConnectionLost(mus::WindowTreeConnection* connection) override;
-  void OnEmbed(mus::Window* root) override;
-  void OnUnembed() override;
-  void OnWindowBoundsChanged(mus::Window* window,
-                             const gfx::Rect& old_bounds,
-                             const gfx::Rect& new_bounds) override;
+  friend class CompositorMusConnection;
+
+  explicit RenderWidgetMusConnection(int routing_id);
+  ~RenderWidgetMusConnection();
+
+  void OnConnectionLost();
+  void OnWindowInputEvent(scoped_ptr<blink::WebInputEvent> input_event,
+                          const base::Closure& ack);
 
   const int routing_id_;
-  mus::Window* root_;
   scoped_ptr<mus::WindowSurfaceBinding> window_surface_binding_;
+  scoped_refptr<CompositorMusConnection> compositor_mus_connection_;
+
+  // Used to verify single threaded access.
+  base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetMusConnection);
 };