Web Animations: Remove confusing interpolation subdirectory.

Source/core/animation/LengthStyleInterpolation.cpp

 // Copyright 2014 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.
 
 #include "config.h"
-#include "core/animation/interpolation/LengthStyleInterpolation.h"
+#include "core/animation/LengthStyleInterpolation.h"
 
 #include "core/css/CSSCalculationValue.h"
 #include "core/css/resolver/StyleBuilder.h"
 
 namespace blink {
 
 bool LengthStyleInterpolation::canCreateFrom(const CSSValue& value)
 {
     if (value.isPrimitiveValue()) {
         const CSSPrimitiveValue& primitiveValue = blink::toCSSPrimitiveValue(value);
@@ skipping 83 matching lines @@
 {
     StyleBuilder::applyProperty(m_id, state, interpolableValueToLength(m_cachedValue.get(), m_range).get());
 }
 
 void LengthStyleInterpolation::trace(Visitor* visitor)
 {
     StyleInterpolation::trace(visitor);
 }
 
 }