Added a nested class to gfx::Animation

ui/gfx/animation/animation_test_api.cc

Index: ui/gfx/animation/animation_test_api.cc
diff --git a/ui/gfx/animation/animation_test_api.cc b/ui/gfx/animation/animation_test_api.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e2d093fa164c852ebe4dc7dc35ffb973788105f6
--- /dev/null
+++ b/ui/gfx/animation/animation_test_api.cc
@@ -0,0 +1,25 @@
+// Copyright 2017 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.
+
+#include "ui/gfx/animation/animation_test_api.h"
+
+#include "base/time/time.h"
+#include "ui/gfx/animation/animation.h"
+
+namespace gfx {
+
+AnimationTestApi::AnimationTestApi(Animation* animation)
+    : animation_(animation) {}
+
+AnimationTestApi::~AnimationTestApi() {}
+
+void AnimationTestApi::SetStartTime(base::TimeTicks ticks) {
+  animation_->SetStartTime(ticks);
+}
+
+void AnimationTestApi::Step(base::TimeTicks ticks) {
+  animation_->Step(ticks);
+}
+
+}  // namespace gfx