Transform animations should not collapse by default when interpolating

cc/animation/animation_curve.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_ANIMATION_CURVE_H_
 #define CC_ANIMATION_ANIMATION_CURVE_H_
 
 #include <memory>
 
 #include "base/time/time.h"
 #include "cc/animation/animation_export.h"
 #include "cc/base/filter_operations.h"
 #include "ui/gfx/geometry/size_f.h"
 #include "ui/gfx/transform.h"
 
 namespace gfx {
 class BoxF;
 }
 
 namespace cc {
 
 class ColorAnimationCurve;
 class FilterAnimationCurve;
 class FloatAnimationCurve;
 class ScrollOffsetAnimationCurve;
 class SizeAnimationCurve;
 class TransformAnimationCurve;
+class TransformOperations;
 
 // An animation curve is a function that returns a value given a time.
 class CC_ANIMATION_EXPORT AnimationCurve {
  public:
   enum CurveType { COLOR, FLOAT, TRANSFORM, FILTER, SCROLL_OFFSET, SIZE };
 
   virtual ~AnimationCurve() {}
 
   virtual base::TimeDelta Duration() const = 0;
   virtual CurveType Type() const = 0;
@@ skipping 26 matching lines @@
   virtual float GetValue(base::TimeDelta t) const = 0;
 
   // Partial Animation implementation.
   CurveType Type() const override;
 };
 
 class CC_ANIMATION_EXPORT TransformAnimationCurve : public AnimationCurve {
  public:
   ~TransformAnimationCurve() override {}
 
-  virtual gfx::Transform GetValue(base::TimeDelta t) const = 0;
+  virtual TransformOperations GetValue(base::TimeDelta t) const = 0;
 
   // Sets |bounds| to be the bounding box for the region within which |box|
   // will move during this animation. If this region cannot be computed,
   // returns false.
   virtual bool AnimatedBoundsForBox(const gfx::BoxF& box,
                                     gfx::BoxF* bounds) const = 0;
 
   // Returns true if this animation is a translation.
   virtual bool IsTranslation() const = 0;
 
@@ skipping 33 matching lines @@
 
   virtual gfx::SizeF GetValue(base::TimeDelta t) const = 0;
 
   // Partial Animation implementation.
   CurveType Type() const override;
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_ANIMATION_CURVE_H_