Blink Compositor Animation: Make Animation and Curve methods non-virtual.

cc/animation/timing_function.h

Index: cc/animation/timing_function.h
diff --git a/cc/animation/timing_function.h b/cc/animation/timing_function.h
index d1807f6f091c90a2cffd947d2f95c20541c1c195..8f021ce735348c7ace44d764a6498a8e21354c8f 100644
--- a/cc/animation/timing_function.h
+++ b/cc/animation/timing_function.h
@@ -18,6 +18,10 @@ class CC_EXPORT TimingFunction {
  public:
   virtual ~TimingFunction();
 
+  // Note that LINEAR is a nullptr TimingFunction (for now).
+  enum class Type { LINEAR, CUBIC_BEZIER, STEPS };
+
+  virtual Type GetType() 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].
@@ -43,15 +47,23 @@ class CC_EXPORT CubicBezierTimingFunction : public TimingFunction {
   ~CubicBezierTimingFunction() override;
 
   // TimingFunction implementation.
+  Type GetType() const override;
   float GetValue(double time) const override;
   float Velocity(double time) const override;
   void Range(float* min, float* max) const override;
   std::unique_ptr<TimingFunction> Clone() const override;
 
+  EaseType ease_type() const { return ease_type_; }
+
  protected:
-  CubicBezierTimingFunction(double x1, double y1, double x2, double y2);
+  CubicBezierTimingFunction(EaseType ease_type,
+                            double x1,
+                            double y1,
+                            double x2,
+                            double y2);
 
   gfx::CubicBezier bezier_;
+  EaseType ease_type_;
 
  private:
   DISALLOW_ASSIGN(CubicBezierTimingFunction);
@@ -99,9 +111,10 @@ class CC_EXPORT StepsTimingFunction : public TimingFunction {
       StepPosition step_position);
   ~StepsTimingFunction() override;
 
+  // TimingFunction implementation.
+  Type GetType() const override;
   float GetValue(double t) const override;
   std::unique_ptr<TimingFunction> Clone() const override;
-
   void Range(float* min, float* max) const override;
   float Velocity(double time) const override;