Make DispatchKeyEventPostIME() asynchronous.

ui/aura/mus/text_input_client_impl.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_AURA_MUS_TEXT_INPUT_CLIENT_IMPL_H_
 #define UI_AURA_MUS_TEXT_INPUT_CLIENT_IMPL_H_
 
 #include "mojo/public/cpp/bindings/binding.h"
 #include "services/ui/public/interfaces/ime/ime.mojom.h"
 #include "ui/base/ime/composition_text.h"
+#include "ui/base/ime/input_method_delegate.h"
 
 namespace ui {
 class TextInputClient;
 }
 
 namespace aura {
 
 // TextInputClientImpl receieves updates from IME drivers over Mojo IPC, and
 // notifies the underlying ui::TextInputClient accordingly.
 class TextInputClientImpl : public ui::mojom::TextInputClient {
  public:
-  explicit TextInputClientImpl(ui::TextInputClient* text_input_client);
+  explicit TextInputClientImpl(ui::TextInputClient* text_input_client,
+                               ui::internal::InputMethodDelegate* delegate);
   ~TextInputClientImpl() override;
 
   ui::mojom::TextInputClientPtr CreateInterfacePtrAndBind();
 
  private:
   // ui::mojom::TextInputClient:
   void SetCompositionText(const ui::CompositionText& composition) override;
   void ConfirmCompositionText() override;
   void ClearCompositionText() override;
   void InsertText(const std::string& text) override;
   void InsertChar(std::unique_ptr<ui::Event> event) override;
+  void DispatchKeyEventPostIME(
+      std::unique_ptr<ui::Event> event,
+      const DispatchKeyEventPostIMECallback& callback) override;
 
   ui::TextInputClient* text_input_client_;
   mojo::Binding<ui::mojom::TextInputClient> binding_;
+  ui::internal::InputMethodDelegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(TextInputClientImpl);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_TEXT_INPUT_CLIENT_IMPL_H_