[Android] Port Scroller.java to C++ and use for fling animations

ui/gfx/gfx.gyp

 # Copyright (c) 2013 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,
   },
   'targets': [
     {
@@ skipping 105 matching lines @@
       'defines': [
         'GFX_IMPLEMENTATION',
       ],
       'sources': [
         'android/device_display_info.cc',
         'android/device_display_info.h',
         'android/gfx_jni_registrar.cc',
         'android/gfx_jni_registrar.h',
         'android/java_bitmap.cc',
         'android/java_bitmap.h',
+        'android/scroller.cc',
+        'android/scroller.h',
         'android/shared_device_display_info.cc',
         'android/shared_device_display_info.h',
         'android/view_configuration.cc',
         'android/view_configuration.h',
         'animation/animation.cc',
         'animation/animation.h',
         'animation/animation_container.cc',
         'animation/animation_container.h',
         'animation/animation_container_element.h',
         'animation/animation_container_observer.h',
@@ skipping 400 matching lines @@
          'variables': {
            'jni_gen_package': 'ui/gfx',
            'jni_generator_ptr_type': 'long'
          },
          'includes': [ '../../build/jni_generator.gypi' ],
        },
      ],
     }],
   ],
 }