Refactors animation to allow for cleaner subclassing. I'm doing this

app/app_base.gypi

 # Copyright (c) 2010 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.
 
 {
   'target_defaults': {
     'variables': {
       'app_base_target': 0,
     },
     'target_conditions': [
@@ skipping 128 matching lines @@
         'gtk_signal.h',
         'gtk_util.cc',
         'gtk_util.h',
         'l10n_util.cc',
         'l10n_util.h',
         'l10n_util_mac.h',
         'l10n_util_mac.mm',
         'l10n_util_posix.cc',
         'l10n_util_win.cc',
         'l10n_util_win.h',
+        'linear_animation.cc',
+        'linear_animation.h',
         'menus/accelerator.h',
         'menus/accelerator_gtk.h',
         'menus/menu_model.cc',
         'menus/menu_model.h',
         'menus/simple_menu_model.cc',
         'menus/simple_menu_model.h',
         'message_box_flags.h',
         'os_exchange_data_provider_gtk.cc',
         'os_exchange_data_provider_gtk.h',
         'os_exchange_data_provider_win.cc',
@@ skipping 28 matching lines @@
         'surface/transport_dib_win.cc',
         'table_model.cc',
         'table_model.h',
         'table_model_observer.h',
         'text_elider.cc',
         'text_elider.h',
         'theme_provider.cc',
         'theme_provider.h',
         'throb_animation.cc',
         'throb_animation.h',
+        'tween.cc',
+        'tween.h',
         'x11_util.cc',
         'x11_util.h',
         'x11_util_internal.h',
         '../third_party/glew/src/glew.c',
       ],
       'conditions': [
         ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {
           'dependencies': [
             # font_gtk.cc uses fontconfig.
             # TODO(evanm): I think this is wrong; it should just use GTK.
@@ skipping 81 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }