Add action for each button on opt-in IME menu.

ash/common/system/chromeos/ime_menu/ime_menu_tray.h

Index: ash/common/system/chromeos/ime_menu/ime_menu_tray.h
diff --git a/ash/common/system/chromeos/ime_menu/ime_menu_tray.h b/ash/common/system/chromeos/ime_menu/ime_menu_tray.h
index 84f6e780815a16ca4b6e3cbe2ce19117692ae44e..184f721305c518693bf4b4d1e44f1b93a2cb8948 100644
--- a/ash/common/system/chromeos/ime_menu/ime_menu_tray.h
+++ b/ash/common/system/chromeos/ime_menu/ime_menu_tray.h
@@ -34,6 +34,9 @@ class ASH_EXPORT ImeMenuTray : public TrayBackgroundView,
   // Shows the IME menu bubble and highlights the button.
   void ShowImeMenuBubble();
 
+  // Hides the IME menu bubble and lowlights the button.
+  void HideImeMenuBubble();
+
   // Returns true if the IME menu bubble has been shown.
   bool IsImeMenuBubbleShown();
 
@@ -69,9 +72,6 @@ class ASH_EXPORT ImeMenuTray : public TrayBackgroundView,
   // Updates the text of the label on the tray.
   void UpdateTrayLabel();
 
-  // Hides the IME menu bubble and lowlights the button.
-  void HideImeMenuBubble();
-
   // Bubble for default and detailed views.
   std::unique_ptr<TrayBubbleWrapper> bubble_;
   ImeListView* ime_list_view_;