Make the virtual keyboard show up on the display with input focus.

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

 // 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.
 
 #ifndef ASH_COMMON_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_TRAY_H_
 #define ASH_COMMON_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_TRAY_H_
 
 #include "ash/common/keyboard/keyboard_ui_observer.h"
 #include "ash/common/system/tray/tray_background_view.h"
 #include "base/macros.h"
@@ skipping 28 matching lines @@
   void OnKeyboardClosed() override;
 
  private:
   // Creates a new border for the icon. The padding is determined based on the
   // alignment of the shelf.
   void SetIconBorderForShelfAlignment();
 
   void ObserveKeyboardController();
   void UnobserveKeyboardController();
 
+  const int64_t display_id_;
+
   // Weak pointer, will be parented by TrayContainer for its lifetime.
   views::ImageView* icon_;
 
   DISALLOW_COPY_AND_ASSIGN(VirtualKeyboardTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_CHROMEOS_VIRTUAL_KEYBOARD_VIRTUAL_KEYBOARD_TRAY_H_