Scroll offset animation curve retargeting.

cc/animation/timing_function.cc

 // Copyright 2012 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 "base/logging.h"
 #include "cc/animation/timing_function.h"
 
 namespace cc {
 
 TimingFunction::TimingFunction() {}
@@ skipping 27 matching lines @@
 }
 
 void CubicBezierTimingFunction::Range(float* min, float* max) const {
   double min_d = 0;
   double max_d = 1;
   bezier_.Range(&min_d, &max_d);
   *min = static_cast<float>(min_d);
   *max = static_cast<float>(max_d);
 }
 
+float CubicBezierTimingFunction::Velocity(double x) const {
+  return static_cast<float>(bezier_.Slope(x));
+}
+
 // These numbers come from
 // http://www.w3.org/TR/css3-transitions/#transition-timing-function_tag.
 scoped_ptr<TimingFunction> EaseTimingFunction::Create() {
   return CubicBezierTimingFunction::Create(
       0.25, 0.1, 0.25, 1.0).PassAs<TimingFunction>();
 }
 
 scoped_ptr<TimingFunction> EaseInTimingFunction::Create() {
   return CubicBezierTimingFunction::Create(
       0.42, 0.0, 1.0, 1.0).PassAs<TimingFunction>();
 }
 
 scoped_ptr<TimingFunction> EaseOutTimingFunction::Create() {
   return CubicBezierTimingFunction::Create(
       0.0, 0.0, 0.58, 1.0).PassAs<TimingFunction>();
 }
 
 scoped_ptr<TimingFunction> EaseInOutTimingFunction::Create() {
   return CubicBezierTimingFunction::Create(
       0.42, 0.0, 0.58, 1).PassAs<TimingFunction>();
 }
 
 }  // namespace cc