Refactoring the ownership of ui::InputMethod.

ui/aura/window_tree_host_win.h

Index: ui/aura/window_tree_host_win.h
diff --git a/ui/aura/window_tree_host_win.h b/ui/aura/window_tree_host_win.h
index 8399c8e12b5209d8d3b024fea3383d10f22d0c15..d8e5173163b16f6628e821d02436a19f9409b403 100644
--- a/ui/aura/window_tree_host_win.h
+++ b/ui/aura/window_tree_host_win.h
@@ -17,7 +17,6 @@ namespace aura {
 
 class AURA_EXPORT WindowTreeHostWin
     : public WindowTreeHost,
-      public ui::EventSource,
       public NON_EXPORTED_BASE(ui::PlatformWindowDelegate) {
  public:
   explicit WindowTreeHostWin(const gfx::Rect& bounds);
@@ -37,9 +36,6 @@ class AURA_EXPORT WindowTreeHostWin
   void MoveCursorToNative(const gfx::Point& location) override;
   void OnCursorVisibilityChangedNative(bool show) override;
 
-  // ui::EventSource:
-  ui::EventProcessor* GetEventProcessor() override;
-
  protected:
   gfx::AcceleratedWidget hwnd() const { return widget_; }