Implement overscroll support for the virtual keyboard.

ui/aura/aura.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 30 matching lines @@
         'client/default_capture_client.cc',
         'client/default_capture_client.h',
         'client/event_client.cc',
         'client/event_client.h',
         'client/focus_change_observer.cc',
         'client/focus_change_observer.h',
         'client/focus_client.cc',
         'client/focus_client.h',
         'client/screen_position_client.cc',
         'client/screen_position_client.h',
+        'client/virtual_keyboard_client.cc',
+        'client/virtual_keyboard_client.h',
+        'client/virtual_keyboard_observer.h',
         'client/visibility_client.cc',
         'client/visibility_client.h',
         'client/window_stacking_client.cc',
         'client/window_stacking_client.h',
         'client/window_tree_client.cc',
         'client/window_tree_client.h',
         'device_list_updater_aurax11.cc',
         'device_list_updater_aurax11.h',
         'env.cc',
         'env.h',
@@ skipping 219 matching lines @@
         ['OS=="linux" and ((use_allocator!="none" and use_allocator!="see_use_tcmalloc") or (use_allocator=="see_use_tcmalloc" and linux_use_tcmalloc==1))', {
           'dependencies': [
            # See http://crbug.com/162998#c4 for why this is needed.
             '../../base/allocator/allocator.gyp:allocator',
           ],
         }],
       ],
     },
   ],
 }