MacViews: Implemented Drag & Drop

ui/views/views.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,
     # Sources lists shared with GN build.
     'views_sources': [
       'accessibility/native_view_accessibility.cc',
       'accessibility/native_view_accessibility.h',
@@ skipping 42 matching lines @@
       'bubble/bubble_dialog_delegate.h',
       'bubble/bubble_frame_view.cc',
       'bubble/bubble_frame_view.h',
       'button_drag_utils.cc',
       'button_drag_utils.h',
       'cocoa/bridged_content_view.h',
       'cocoa/bridged_content_view.mm',
       'cocoa/bridged_native_widget.h',
       'cocoa/bridged_native_widget.mm',
       'cocoa/bridged_native_widget_owner.h',
+      'cocoa/drag_drop_client_mac.h',
+      'cocoa/drag_drop_client_mac.mm',
       'cocoa/cocoa_mouse_capture.h',
       'cocoa/cocoa_mouse_capture.mm',
       'cocoa/cocoa_mouse_capture_delegate.h',
       'cocoa/native_widget_mac_nswindow.h',
       'cocoa/native_widget_mac_nswindow.mm',
       'cocoa/tooltip_manager_mac.h',
       'cocoa/tooltip_manager_mac.mm',
       'cocoa/views_nswindow_delegate.h',
       'cocoa/views_nswindow_delegate.mm',
       'cocoa/views_scrollbar_bridge.h',
@@ skipping 502 matching lines @@
       'animation/ink_drop_impl_unittest.cc',
       'animation/ink_drop_ripple_unittest.cc',
       'animation/ink_drop_hover_unittest.cc',
       'animation/square_ink_drop_ripple_unittest.cc',
       'bubble/bubble_border_unittest.cc',
       'bubble/bubble_dialog_delegate_unittest.cc',
       'bubble/bubble_frame_view_unittest.cc',
       'bubble/bubble_window_targeter_unittest.cc',
       'cocoa/bridged_native_widget_unittest.mm',
       'cocoa/cocoa_mouse_capture_unittest.mm',
+      'cocoa/drag_drop_client_mac_unittest.mm',
       'controls/button/blue_button_unittest.cc',
       'controls/button/custom_button_unittest.cc',
       'controls/button/image_button_unittest.cc',
       'controls/button/label_button_unittest.cc',
       'controls/button/menu_button_unittest.cc',
       'controls/combobox/combobox_unittest.cc',
       'controls/label_unittest.cc',
       'controls/menu/menu_controller_unittest.cc',
       'controls/menu/menu_item_view_unittest.cc',
       'controls/menu/menu_model_adapter_unittest.cc',
@@ skipping 444 matching lines @@
                 '../aura/aura.gyp:aura',
                 '../wm/wm.gyp:wm',
               ],
             }],
           ],
         },  # target_name: macviews_interactive_ui_tests
       ],  # targets
     }],
   ],  # conditions
 }