Animation: Allow CC per-curve timing functions to be steps timing functions

public/platform/WebFloatAnimationCurve.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 28 matching lines @@
 
     // Adds the keyframe with the default timing function (ease).
     virtual void add(const WebFloatKeyframe&) = 0;
     virtual void add(const WebFloatKeyframe&, TimingFunctionType) = 0;
     // Adds the keyframe with a custom, bezier timing function. Note, it is
     // assumed that x0 = y0 = 0, and x3 = y3 = 1.
     virtual void add(const WebFloatKeyframe&, double x1, double y1, double x2, double y2) = 0;
     // Adds the keyframe with a steps timing function.
     virtual void add(const WebFloatKeyframe&, int steps, float stepsStartOffset) = 0;
 
+    virtual void setLinearTimingFunction() = 0;
+    virtual void setCubicBezierTimingFunction(TimingFunctionType) = 0;
+    virtual void setCubicBezierTimingFunction(double x1, double y1, double x2, double y2) = 0;
+    virtual void setStepsTimingFunction(int numberOfSteps, float stepsStartOffset) = 0;
+
     virtual float getValue(double time) const = 0;
 };
 
 } // namespace blink
 
 #endif // WebFloatAnimationCurve_h