Added a nested class to gfx::Animation

ui/gfx/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/ui.gni")
 import("//device/vr/features/features.gni")
 import("//testing/test.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
 if (is_android) {
@@ skipping 560 matching lines @@
   defines = [ "GFX_SWITCHES_IMPLEMENTATION" ]
 
   deps = [
     "//base",
   ]
 }
 
 static_library("test_support") {
   testonly = true
   sources = [
+    "animation/animation_test_api.cc",
+    "animation/animation_test_api.h",
     "animation/test_animation_delegate.h",
     "geometry/test/rect_test_util.cc",
     "geometry/test/rect_test_util.h",
     "image/image_unittest_util.cc",
     "image/image_unittest_util.h",
     "image/image_unittest_util_ios.mm",
     "image/image_unittest_util_mac.mm",
     "test/fontconfig_util_linux.cc",
     "test/fontconfig_util_linux.h",
     "test/gfx_util.cc",
@@ skipping 208 matching lines @@
 
 fuzzer_test("color_transform_fuzztest") {
   sources = [
     "color_transform_fuzzer.cc",
   ]
   deps = [
     ":gfx",
   ]
   libfuzzer_options = [ "max_len=1024" ]
 }