Web Animations: Remove confusing interpolation subdirectory.

Source/core/animation/css/CSSAnimations.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 16 matching lines @@
  * (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 CSSAnimations_h
 #define CSSAnimations_h
 
 #include "core/animation/Animation.h"
 #include "core/animation/AnimationPlayer.h"
 #include "core/animation/InertAnimation.h"
-#include "core/animation/interpolation/Interpolation.h"
+#include "core/animation/Interpolation.h"
 #include "core/css/StylePropertySet.h"
 #include "core/dom/Document.h"
 #include "core/rendering/style/RenderStyleConstants.h"
 #include "wtf/HashMap.h"
 #include "wtf/Vector.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class CSSTransitionData;
@@ skipping 201 matching lines @@
         const CSSPropertyID m_property;
         AnimationNode::Phase m_previousPhase;
     };
 };
 
 } // namespace blink
 
 WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(blink::CSSAnimationUpdate::NewAnimation);
 
 #endif