Refactors StackingController::GetDefaultParent to ash/wm/common

ash/wm/common/ash_wm_common.gyp

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'ash_wm_common',
       'type': '<(component)',
       'dependencies': [
@@ skipping 12 matching lines @@
         '../../../ui/wm/wm.gyp:wm',
       ],
       'defines': [
         'ASH_WM_COMMON_IMPLEMENTATION',
       ],
       'sources': [
         'always_on_top_controller.cc',
         'always_on_top_controller.h',
         'background_animator.cc',
         'background_animator.h',
+        'container_finder.cc',
+        'container_finder.h',
         'default_state.cc',
         'default_state.h',
         'default_window_resizer.cc',
         'default_window_resizer.h',
         'dock/docked_window_layout_manager.cc',
         'dock/docked_window_layout_manager.h',
         'dock/docked_window_layout_manager_observer.h',
         'dock/docked_window_resizer.cc',
         'dock/docked_window_resizer.h',
         'drag_details.cc',
@@ skipping 72 matching lines @@
       ],
       'conditions': [
         ['OS=="win"', {
           # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
           'msvs_disabled_warnings': [ 4267, ],
         }],
       ],
     },
   ],
 }