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

third_party/WebKit/Source/core/css/parser/CSSParser.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 "core/css/parser/CSSParser.h"
 
 #include "core/css/CSSColorValue.h"
 #include "core/css/CSSKeyframeRule.h"
 #include "core/css/StyleColor.h"
 #include "core/css/StyleRule.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/css/parser/CSSParserFastPaths.h"
 #include "core/css/parser/CSSParserImpl.h"
 #include "core/css/parser/CSSPropertyParser.h"
 #include "core/css/parser/CSSSelectorParser.h"
 #include "core/css/parser/CSSSupportsParser.h"
 #include "core/css/parser/CSSTokenizer.h"
 #include "core/css/parser/CSSVariableParser.h"
 #include "core/layout/LayoutTheme.h"
 #include <memory>
 
 namespace blink {
 
+using namespace cssvalue;
+
 bool CSSParser::parseDeclarationList(const CSSParserContext* context,
                                      MutableStylePropertySet* propertySet,
                                      const String& declaration) {
   return CSSParserImpl::parseDeclarationList(propertySet, declaration, context);
 }
 
 void CSSParser::parseDeclarationListForInspector(
     const CSSParserContext* context,
     const String& declaration,
     CSSParserObserver& observer) {
@@ skipping 208 matching lines @@
   builder.append(propertyValue);
   builder.append("; }");
   StyleRuleBase* rule = parseRule(context, nullptr, builder.toString());
   if (!rule || !rule->isFontFaceRule())
     return nullptr;
   return toStyleRuleFontFace(rule)->properties().getPropertyCSSValue(
       propertyID);
 }
 
 }  // namespace blink