Move Animatable* hierarchy into new folder.

Source/core/animation/animatable/AnimatableLengthBox.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef AnimatableLengthBox_h
 #define AnimatableLengthBox_h
 
-#include "core/animation/AnimatableValue.h"
+#include "core/animation/animatable/AnimatableValue.h"
 
 namespace WebCore {
 
 class AnimatableLengthBox FINAL : public AnimatableValue {
 public:
     virtual ~AnimatableLengthBox() { }
     static PassRefPtrWillBeRawPtr<AnimatableLengthBox> create(PassRefPtrWillBeRawPtr<AnimatableValue> left, PassRefPtrWillBeRawPtr<AnimatableValue> right, PassRefPtrWillBeRawPtr<AnimatableValue> top, PassRefPtrWillBeRawPtr<AnimatableValue> bottom)
     {
         return adoptRefWillBeNoop(new AnimatableLengthBox(left, right, top, bottom));
     }
@@ skipping 22 matching lines @@
     RefPtrWillBeMember<AnimatableValue> m_right;
     RefPtrWillBeMember<AnimatableValue> m_top;
     RefPtrWillBeMember<AnimatableValue> m_bottom;
 };
 
 DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableLengthBox, isLengthBox());
 
 } // namespace WebCore
 
 #endif // AnimatableLengthBox_h