GSB uses delta_hints to calculate scrolling chain.

ui/events/blink/input_handler_proxy_unittest.cc

 // Copyright 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.
 
 #include "ui/events/blink/input_handler_proxy.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/macros.h"
@@ skipping 155 matching lines @@
   MOCK_METHOD0(PinchGestureEnd, void());
 
   MOCK_METHOD0(SetNeedsAnimateInput, void());
 
   MOCK_METHOD2(ScrollBegin,
                ScrollStatus(cc::ScrollState*,
                             cc::InputHandler::ScrollInputType type));
   MOCK_METHOD2(RootScrollBegin,
                ScrollStatus(cc::ScrollState*,
                             cc::InputHandler::ScrollInputType type));
-  MOCK_METHOD1(ScrollAnimatedBegin,
-               ScrollStatus(const gfx::Point& viewport_point));
+  MOCK_METHOD1(ScrollAnimatedBegin, ScrollStatus(cc::ScrollState*));
   MOCK_METHOD3(ScrollAnimated,
                ScrollStatus(const gfx::Point& viewport_point,
                             const gfx::Vector2dF& scroll_delta,
                             base::TimeDelta));
   MOCK_METHOD1(ScrollBy, cc::InputHandlerScrollResult(cc::ScrollState*));
   MOCK_METHOD1(ScrollEnd, void(cc::ScrollState*));
   MOCK_METHOD0(FlingScrollBegin, cc::InputHandler::ScrollStatus());
   MOCK_METHOD0(ScrollingShouldSwitchtoMainThread, bool());
 
   std::unique_ptr<cc::SwapPromiseMonitor> CreateLatencyInfoSwapPromiseMonitor(
@@ skipping 3724 matching lines @@
 INSTANTIATE_TEST_CASE_P(AnimateInput,
                         InputHandlerProxyWithoutWheelScrollLatchingTest,
                         testing::ValuesIn(test_types));
 
 INSTANTIATE_TEST_CASE_P(InputHandlerProxyEventQueueTests,
                         InputHandlerProxyEventQueueTest,
                         testing::Bool());
 
 }  // namespace test
 }  // namespace ui