Use EventHandler for IME

ash/host/ash_window_tree_host_unified.h

Index: ash/host/ash_window_tree_host_unified.h
diff --git a/ash/host/ash_window_tree_host_unified.h b/ash/host/ash_window_tree_host_unified.h
index 2f8b04280441b55738c568dbd30825e38784b355..1384ff0d94c0ae6b68e3288b9c5a72c431269c6c 100644
--- a/ash/host/ash_window_tree_host_unified.h
+++ b/ash/host/ash_window_tree_host_unified.h
@@ -64,6 +64,12 @@ class AshWindowTreeHostUnified : public AshWindowTreeHost,
   // aura::WindowObserver:
   void OnWindowDestroying(aura::Window* window) override;
 
+  // ui::internal::InputMethodDelegate:
+  bool DispatchKeyEventPostIME(const ui::KeyEvent& event) override;
+
+  // ui::EventSource:
+  ui::EventDispatchDetails DeliverEventToProcessor(ui::Event* event) override;
+
   std::vector<AshWindowTreeHost*> mirroring_hosts_;
 
   gfx::Rect bounds_;