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

third_party/WebKit/Source/core/css/CSSColorValue.h

 // 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.
 
 #ifndef CSSColorValue_h
 #define CSSColorValue_h
 
 #include "core/css/CSSValue.h"
 #include "platform/graphics/Color.h"
 #include "wtf/PassRefPtr.h"
 
 namespace blink {
 
+class CSSValuePool;
+
+namespace cssvalue {
+
 // Represents the non-keyword subset of <color>.
 class CSSColorValue : public CSSValue {
  public:
   // TODO(sashab): Make this create() method take a Color instead.
   static CSSColorValue* create(RGBA32 color);
 
   String customCSSText() const {
     return m_color.serializedAsCSSComponentValue();
   }
 
   Color value() const { return m_color; }
 
   bool equals(const CSSColorValue& other) const {
     return m_color == other.m_color;
   }
 
   DEFINE_INLINE_TRACE_AFTER_DISPATCH() {
     CSSValue::traceAfterDispatch(visitor);
   }
 
  private:
-  friend class CSSValuePool;
+  friend class ::blink::CSSValuePool;
 
   CSSColorValue(Color color) : CSSValue(ColorClass), m_color(color) {}
 
   Color m_color;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSColorValue, isColorValue());
 
+}  // namespace cssvalue
 }  // namespace blink
 
 #endif  // CSSColorValue_h