Add Vector2d classes that represent offsets, instead of using Point.

WATCHLISTS

 # 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.
 
 # Watchlist Rules
 # Refer: http://dev.chromium.org/developers/contributing-code/watchlists
 
 # IMPORTANT: The regular expression filepath is tested against each path using
 # re.search, so it is not usually necessary to add .*.
 
@@ skipping 181 matching lines @@
     'fullscreen_controller': {
       'filepath': 'fullscreen_controller',
     },
     'gfx_image': {
       'filepath': 'ui/gfx/image/',
     },
     'gfx_geometry': {
       'filepath': 'ui/gfx/rect|'\
                   'ui/gfx/point|'\
                   'ui/gfx/size|'\
-                  'ui/gfx/transform',
+                  'ui/gfx/transform|'\
+                  'ui/gfx/vector2d',
     },
     'gpu': {
       'filepath': 'gpu/',
     },
     'history_ui': {
       'filepath': 'chrome/browser/resources/history',
     },
     'i18n': {
       'filepath': 'base/i18n/|base/string|l10n|icu|'\
         'locale_settings|encoding',
@@ skipping 408 matching lines @@
                    'groby+watch@chromium.org',
                    'rouslan+watch@chromium.org'],
     'website_settings': ['markusheintz@chromium.org'],
     'webkit': ['darin-cc@chromium.org'],
     'worker': ['jam@chromium.org'],
     'x11': ['derat+watch@chromium.org',
             'sadrul@chromium.org',
             'yusukes+watch@chromium.org'],
   },
 }