Do not clamp y values on internal knots of timing function bezier curves

cc/animation/timing_function.h

 // 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.
 
 #ifndef CC_ANIMATION_TIMING_FUNCTION_H_
 #define CC_ANIMATION_TIMING_FUNCTION_H_
 
 #include "cc/animation/animation_curve.h"
 #include "cc/base/cc_export.h"
 #include "third_party/skia/include/core/SkScalar.h"
@@ skipping 21 matching lines @@
                                                       double x2, double y2);
   virtual ~CubicBezierTimingFunction();
 
   // Partial implementation of FloatAnimationCurve.
   virtual float GetValue(double time) const OVERRIDE;
   virtual scoped_ptr<AnimationCurve> Clone() const OVERRIDE;
 
  protected:
   CubicBezierTimingFunction(double x1, double y1, double x2, double y2);
 
-  SkScalar x1_;
-  SkScalar y1_;
-  SkScalar x2_;
-  SkScalar y2_;
+  double x1_;
+  double y1_;
+  double x2_;
+  double y2_;
 
  private:
   DISALLOW_ASSIGN(CubicBezierTimingFunction);
 };
 
 class CC_EXPORT EaseTimingFunction {
  public:
   static scoped_ptr<TimingFunction> Create();
 
  private:
@@ skipping 20 matching lines @@
  public:
   static scoped_ptr<TimingFunction> Create();
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(EaseInOutTimingFunction);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_TIMING_FUNCTION_H_