Add chrome.inputMethodPrivate.onImeMenuActivationChanged API.

chrome/browser/chromeos/extensions/ime_menu_event_router.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_CHROMEOS_EXTENSIONS_IME_MENU_EVENT_ROUTER_H_
+#define CHROME_BROWSER_CHROMEOS_EXTENSIONS_IME_MENU_EVENT_ROUTER_H_
+
+#include "base/macros.h"
+#include "ui/base/ime/chromeos/input_method_manager.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace chromeos {
+
+// Event router class for the IME Menu activated/deactivate events.

[Devlin, 2016/01/13 18:11:27]

Can you document the lifetime of this object, since it is required that it's
restricted to the lifetime of the InputMethodManager and the EventRouter?

[Azure Wei, 2016/01/14 09:38:26]

Done.

+class ExtensionImeMenuEventRouter
+    : public input_method::InputMethodManager::ImeMenuObserver {
+ public:
+  explicit ExtensionImeMenuEventRouter(content::BrowserContext* context);
+  ~ExtensionImeMenuEventRouter() override;
+
+  // input_method::InputMethodManager::ImeMenuObserver:
+  void ImeMenuActivationChanged(bool activation) override;
+
+ private:
+  content::BrowserContext* context_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionImeMenuEventRouter);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_IME_MENU_EVENT_ROUTER_H_