Do not activate TrayBubbleView by default

ash/system/ime_menu/ime_menu_tray.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 ASH_SYSTEM_IME_MENU_IME_MENU_TRAY_H_
 #define ASH_SYSTEM_IME_MENU_IME_MENU_TRAY_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/ime/ime_observer.h"
 #include "ash/system/tray/ime_info.h"
@@ skipping 53 matching lines @@
   bool PerformAction(const ui::Event& event) override;
 
   // IMEObserver:
   void OnIMERefresh() override;
   void OnIMEMenuActivationChanged(bool is_activated) override;
 
   // views::TrayBubbleView::Delegate:
   void BubbleViewDestroyed() override;
   void OnMouseEnteredView() override;
   void OnMouseExitedView() override;
+  void RegisterAccelerators(const std::vector<ui::Accelerator>& accelerators,
+                            views::TrayBubbleView* tray_bubble_view) override;
+  void UnregisterAllAccelerators(
+      views::TrayBubbleView* tray_bubble_view) override;
   base::string16 GetAccessibleNameForBubble() override;
+  bool ShouldEnableExtraKeyboardAccessibility() override;
   void HideBubble(const views::TrayBubbleView* bubble_view) override;
 
   // keyboard::KeyboardControllerObserver:
   void OnKeyboardBoundsChanging(const gfx::Rect& new_bounds) override;
   void OnKeyboardClosed() override;
   void OnKeyboardHidden() override;
 
   // VirtualKeyboardObserver:
   void OnKeyboardSuppressionChanged(bool suppressed) override;
 
@@ skipping 22 matching lines @@
   bool show_bubble_after_keyboard_hidden_;
 
   base::WeakPtrFactory<ImeMenuTray> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ImeMenuTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_IME_MENU_IME_MENU_TRAY_H_