IME for Mus: Use ui::InputMethodChromeOS to provide logic for ime driver.

chrome/browser/ui/views/ime_driver/simple_input_method.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 CHROME_BROWSER_UI_VIEWS_IME_DRIVER_SIMPLE_INPUT_METHOD_H_
+#define CHROME_BROWSER_UI_VIEWS_IME_DRIVER_SIMPLE_INPUT_METHOD_H_
+
+#include "services/ui/public/interfaces/ime/ime.mojom.h"
+
+// This is to be used on platforms where a proper implementation of
+// ui::mojom::InputMethod is missing. It doesn't handle any events and calls
+// the callback with false, which will result in client code handling events
+// locally.
+class SimpleInputMethod : public ui::mojom::InputMethod {
+ public:
+  SimpleInputMethod();
+  ~SimpleInputMethod() override;
+
+  // ui::mojom::InputMethod:
+  void OnTextInputModeChanged(
+      ui::mojom::TextInputMode text_input_mode) override;
+  void OnTextInputTypeChanged(
+      ui::mojom::TextInputType text_input_type) override;
+  void OnCaretBoundsChanged(const gfx::Rect& caret_bounds) override;
+  void ProcessKeyEvent(std::unique_ptr<ui::Event> key_event,
+                       const ProcessKeyEventCallback& callback) override;
+  void CancelComposition() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SimpleInputMethod);
+};
+
+#endif  // CHROME_BROWSER_UI_VIEWS_IME_DRIVER_SIMPLE_INPUT_METHOD_H_