CC: Stop TimingFunction inheriting from AnimationCurve.

Simplifies code as TimingFunction has no logical reason to inherit from AnimationCurve (apart from sharing a few method names). Make code more clear.

BUG=

Review URL: https://codereview.chromium.org/606543002

Cr-Commit-Position: refs/heads/master@{#296862}

cc/animation/keyframed_animation_curve.cc

@@ -40,14 +40,6 @@ float GetProgress(double t, size_t i, const Keyframes& keyframes) {
   return progress;
 }
 
-scoped_ptr<TimingFunction> CloneTimingFunction(
-    const TimingFunction* timing_function) {
-  DCHECK(timing_function);
-  scoped_ptr<AnimationCurve> curve(timing_function->Clone());
-  return scoped_ptr<TimingFunction>(
-      static_cast<TimingFunction*>(curve.release()));
-}
-
 }  // namespace
 
 Keyframe::Keyframe(double time, scoped_ptr<TimingFunction> timing_function)
@@ -81,7 +73,7 @@ SkColor ColorKeyframe::Value() const { return value_; }
 scoped_ptr<ColorKeyframe> ColorKeyframe::Clone() const {
   scoped_ptr<TimingFunction> func;
   if (timing_function())
-    func = CloneTimingFunction(timing_function());
+    func = timing_function()->Clone();
   return ColorKeyframe::Create(Time(), Value(), func.Pass());
 }
 
@@ -108,7 +100,7 @@ float FloatKeyframe::Value() const {
 scoped_ptr<FloatKeyframe> FloatKeyframe::Clone() const {
   scoped_ptr<TimingFunction> func;
   if (timing_function())
-    func = CloneTimingFunction(timing_function());
+    func = timing_function()->Clone();
   return FloatKeyframe::Create(Time(), Value(), func.Pass());
 }
 
@@ -135,7 +127,7 @@ const TransformOperations& TransformKeyframe::Value() const {
 scoped_ptr<TransformKeyframe> TransformKeyframe::Clone() const {
   scoped_ptr<TimingFunction> func;
   if (timing_function())
-    func = CloneTimingFunction(timing_function());
+    func = timing_function()->Clone();
   return TransformKeyframe::Create(Time(), Value(), func.Pass());
 }
 
@@ -162,7 +154,7 @@ const FilterOperations& FilterKeyframe::Value() const {
 scoped_ptr<FilterKeyframe> FilterKeyframe::Clone() const {
   scoped_ptr<TimingFunction> func;
   if (timing_function())
-    func = CloneTimingFunction(timing_function());
+    func = timing_function()->Clone();
   return FilterKeyframe::Create(Time(), Value(), func.Pass());
 }
 

cc/animation/timing_function.cc

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "cc/animation/timing_function.h"
 
 namespace cc {
@@ -11,10 +12,6 @@ TimingFunction::TimingFunction() {}
 
 TimingFunction::~TimingFunction() {}
 
-double TimingFunction::Duration() const {
-  return 1.0;
-}
-
 scoped_ptr<CubicBezierTimingFunction> CubicBezierTimingFunction::Create(
     double x1, double y1, double x2, double y2) {
   return make_scoped_ptr(new CubicBezierTimingFunction(x1, y1, x2, y2));
@@ -32,9 +29,8 @@ float CubicBezierTimingFunction::GetValue(double x) const {
   return static_cast<float>(bezier_.Solve(x));
 }
 
-scoped_ptr<AnimationCurve> CubicBezierTimingFunction::Clone() const {
-  return make_scoped_ptr(
-      new CubicBezierTimingFunction(*this)).PassAs<AnimationCurve>();
+float CubicBezierTimingFunction::Velocity(double x) const {
+  return static_cast<float>(bezier_.Slope(x));
 }
 
 void CubicBezierTimingFunction::Range(float* min, float* max) const {
@@ -45,8 +41,9 @@ void CubicBezierTimingFunction::Range(float* min, float* max) const {
   *max = static_cast<float>(max_d);
 }
 
-float CubicBezierTimingFunction::Velocity(double x) const {
-  return static_cast<float>(bezier_.Slope(x));
+scoped_ptr<TimingFunction> CubicBezierTimingFunction::Clone() const {
+  return make_scoped_ptr(new CubicBezierTimingFunction(*this))
+      .PassAs<TimingFunction>();
 }
 
 // These numbers come from

cc/animation/timing_function.h

@@ -5,24 +5,21 @@
 #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 "ui/gfx/geometry/cubic_bezier.h"
 
 namespace cc {
 
 // See http://www.w3.org/TR/css3-transitions/.
-class CC_EXPORT TimingFunction : public FloatAnimationCurve {
+class CC_EXPORT TimingFunction {
  public:
   virtual ~TimingFunction();
 
-  // Partial implementation of FloatAnimationCurve.
-  virtual double Duration() const OVERRIDE;
-
-  // The smallest and largest values returned by GetValue for inputs in
-  // [0, 1].
-  virtual void Range(float* min, float* max) const = 0;
+  virtual float GetValue(double t) const = 0;
   virtual float Velocity(double time) const = 0;
+  // The smallest and largest values returned by GetValue for inputs in [0, 1].
+  virtual void Range(float* min, float* max) const = 0;
+  virtual scoped_ptr<TimingFunction> Clone() const = 0;
 
  protected:
   TimingFunction();
@@ -37,12 +34,11 @@ class CC_EXPORT CubicBezierTimingFunction : public TimingFunction {
                                                       double x2, double y2);
   virtual ~CubicBezierTimingFunction();
 
-  // Partial implementation of FloatAnimationCurve.
+  // TimingFunction implementation.
   virtual float GetValue(double time) const OVERRIDE;
-  virtual scoped_ptr<AnimationCurve> Clone() const OVERRIDE;
-
-  virtual void Range(float* min, float* max) const OVERRIDE;
   virtual float Velocity(double time) const OVERRIDE;
+  virtual void Range(float* min, float* max) const OVERRIDE;
+  virtual scoped_ptr<TimingFunction> Clone() const OVERRIDE;
 
  protected:
   CubicBezierTimingFunction(double x1, double y1, double x2, double y2);

cc/trees/layer_tree_host_unittest_animation.cc

@@ -697,7 +697,7 @@ class LayerTreeHostAnimationTestLayerAddedWithAnimation
       layer->set_layer_animation_delegate(this);
 
       // Any valid AnimationCurve will do here.
-      scoped_ptr<AnimationCurve> curve(EaseTimingFunction::Create());
+      scoped_ptr<AnimationCurve> curve(new FakeFloatAnimationCurve());
       scoped_ptr<Animation> animation(
           Animation::Create(curve.Pass(), 1, 1,
                                   Animation::Opacity));