Introduce the nested namespace ::blink::cssvalue, start with CSSColorValue.

third_party/WebKit/Source/core/animation/CSSColorInterpolationType.cpp

 // Copyright 2015 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 "core/animation/CSSColorInterpolationType.h"
 
 #include "core/animation/ColorPropertyFunctions.h"
 #include "core/css/CSSColorValue.h"
 #include "core/css/CSSIdentifierValue.h"
 #include "core/css/resolver/StyleResolverState.h"
 #include "core/layout/LayoutTheme.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
+using namespace cssvalue;
+
 enum InterpolableColorIndex : unsigned {
   Red,
   Green,
   Blue,
   Alpha,
   Currentcolor,
   WebkitActivelink,
   WebkitLink,
   QuirkInherit,
   InterpolableColorIndexCount,
@@ skipping 251 matching lines @@
 const CSSValue* CSSColorInterpolationType::createCSSValue(
     const InterpolableValue& interpolableValue,
     const NonInterpolableValue*,
     const StyleResolverState& state) const {
   const InterpolableList& colorPair = toInterpolableList(interpolableValue);
   Color color = resolveInterpolableColor(*colorPair.get(Unvisited), state);
   return CSSColorValue::create(color.rgb());
 }
 
 }  // namespace blink