Refactor screen/monitor so that gfx::Screen returns monitor object.

ui/ui.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,
   },
   'includes': [
     'ui_resources.gypi',
@@ skipping 299 matching lines @@
         'gfx/image/image_mac.mm',
         'gfx/image/image_util.cc',
         'gfx/image/image_util.h',
         'gfx/insets.cc',
         'gfx/insets.h',
         'gfx/interpolated_transform.h',
         'gfx/interpolated_transform.cc',
         'gfx/mac/nsimage_cache.h',
         'gfx/mac/nsimage_cache.mm',
         'gfx/mac/scoped_ns_disable_screen_updates.h',
+        'gfx/monitor.cc',
+        'gfx/monitor.h',
+        'gfx/monitor_observer.cc',
+        'gfx/monitor_observer.h',
         'gfx/native_theme.cc',
         'gfx/native_theme.h',
         'gfx/native_theme_android.cc',
         'gfx/native_theme_android.h',
         'gfx/native_theme_aura.cc',
         'gfx/native_theme_aura.h',
         'gfx/native_theme_base.cc',
         'gfx/native_theme_base.h',
         'gfx/native_theme_gtk.cc',
         'gfx/native_theme_gtk.h',
@@ skipping 21 matching lines @@
         'gfx/rect.cc',
         'gfx/rect.h',
         'gfx/rect_base.h',
         'gfx/rect_base_impl.h',
         'gfx/render_text.cc',
         'gfx/render_text.h',
         'gfx/render_text_linux.cc',
         'gfx/render_text_linux.h',
         'gfx/render_text_win.cc',
         'gfx/render_text_win.h',
+        'gfx/screen.cc',
         'gfx/screen.h',
         'gfx/screen_android.cc',
-        'gfx/screen_ash.cc',
+        'gfx/screen_aura.cc',
         'gfx/screen_gtk.cc',
+        'gfx/screen_impl.h',
         'gfx/screen_mac.mm',
         'gfx/screen_win.cc',
         'gfx/scoped_cg_context_save_gstate_mac.h',
         'gfx/scoped_ns_graphics_context_save_gstate_mac.h',
         'gfx/scoped_ns_graphics_context_save_gstate_mac.mm',
         'gfx/scrollbar_size.cc',
         'gfx/scrollbar_size.h',
         'gfx/selection_model.cc',
         'gfx/selection_model.h',
         'gfx/shadow_value.cc',
@@ skipping 348 matching lines @@
                 'shutil.copyfile(\'<(ui_copy_target)\', \'<(ui_copy_dest)\'); ' \
                 'os.chmod(\'<(ui_copy_dest)\', 0700)'
               ]
             }
           ],
         },
       ],
     }],
   ],
 }