Refactoring the ownership of ui::InputMethod.

ui/aura/remote_window_tree_host_win.h

Index: ui/aura/remote_window_tree_host_win.h
diff --git a/ui/aura/remote_window_tree_host_win.h b/ui/aura/remote_window_tree_host_win.h
index 4cde32c9cf7ad5f5c0015923e34ef48300394b93..1bfd51f0926b47f34f45d64f392a31a399fe45cb 100644
--- a/ui/aura/remote_window_tree_host_win.h
+++ b/ui/aura/remote_window_tree_host_win.h
@@ -40,7 +40,6 @@ namespace aura {
 // frontend process, which forwards input events to this class.
 class AURA_EXPORT RemoteWindowTreeHostWin
     : public WindowTreeHost,
-      public ui::EventSource,
       public ui::internal::RemoteInputMethodDelegateWin {
  public:
   // Returns the current RemoteWindowTreeHostWin. This does *not* create a
@@ -129,9 +128,6 @@ class AURA_EXPORT RemoteWindowTreeHostWin
   void MoveCursorToNative(const gfx::Point& location) override;
   void OnCursorVisibilityChangedNative(bool show) override;
 
-  // ui::EventSource:
-  ui::EventProcessor* GetEventProcessor() override;
-
   // ui::internal::RemoteInputMethodDelegateWin overrides:
   void CancelComposition() override;
   void OnTextInputClientUpdated(