IME for Mus: Send ack for key events after IME driver processes the event.

ui/views/mus/text_input_client_impl.h

Index: ui/views/mus/text_input_client_impl.h
diff --git a/ui/views/mus/text_input_client_impl.h b/ui/views/mus/text_input_client_impl.h
index cb51a6cd9137c267d63b66ab71cc6c370fe7c1a7..24b282781dc9ee6f220644ada973a069d9ee4eee 100644
--- a/ui/views/mus/text_input_client_impl.h
+++ b/ui/views/mus/text_input_client_impl.h
@@ -20,8 +20,7 @@ class InputMethodMus;
 // notifies the underlying ui::TextInputClient accordingly.
 class TextInputClientImpl : public ui::mojom::TextInputClient {
  public:
-  TextInputClientImpl(ui::TextInputClient* text_input_client,
-                      InputMethodMus* input_method);
+  explicit TextInputClientImpl(ui::TextInputClient* text_input_client);
   ~TextInputClientImpl() override;
 
   ui::mojom::TextInputClientPtr CreateInterfacePtrAndBind();
@@ -29,10 +28,8 @@ class TextInputClientImpl : public ui::mojom::TextInputClient {
  private:
   // ui::mojom::TextInputClient:
   void OnCompositionEvent(ui::mojom::CompositionEventPtr event) override;
-  void OnUnhandledEvent(std::unique_ptr<ui::Event> key_event) override;
 
   ui::TextInputClient* text_input_client_;
-  InputMethodMus* input_method_;
   mojo::Binding<ui::mojom::TextInputClient> binding_;
 
   DISALLOW_COPY_AND_ASSIGN(TextInputClientImpl);