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

ash/common/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc

 // Copyright 2014 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.
 
 #include "ash/common/system/chromeos/virtual_keyboard/virtual_keyboard_tray.h"
 
 #include <algorithm>
 
 #include "ash/common/keyboard/keyboard_ui.h"
 #include "ash/common/material_design/material_design_controller.h"
@@ skipping 79 matching lines @@
     // Try unobserving keyboard controller, in case it is not yet destroyed.
     UnobserveKeyboardController();
   }
 }
 
 void VirtualKeyboardTray::OnKeyboardBoundsChanging(
     const gfx::Rect& new_bounds) {
   SetDrawBackgroundAsActive(!new_bounds.IsEmpty());
 }
 
+void VirtualKeyboardTray::OnKeyboardHidden() {}
+
 void VirtualKeyboardTray::SetIconBorderForShelfAlignment() {
   // Every time shelf alignment is updated, StatusAreaWidgetDelegate resets the
   // border to a non-null border. So, we need to remove it.
   if (!ash::MaterialDesignController::IsShelfMaterial())
     tray_container()->SetBorder(views::Border::NullBorder());
   const gfx::ImageSkia& image = icon_->GetImage();
   const int size = GetTrayConstant(VIRTUAL_KEYBOARD_BUTTON_SIZE);
   const int vertical_padding = (size - image.height()) / 2;
   int horizontal_padding = (size - image.width()) / 2;
   if (!ash::MaterialDesignController::IsShelfMaterial() &&
@@ skipping 15 matching lines @@
 }
 
 void VirtualKeyboardTray::UnobserveKeyboardController() {
   keyboard::KeyboardController* keyboard_controller =
       keyboard::KeyboardController::GetInstance();
   if (keyboard_controller)
     keyboard_controller->RemoveObserver(this);
 }
 
 }  // namespace ash