Make CSSParserImpl::m_context a const reference to avoid copies

third_party/WebKit/Source/core/css/parser/CSSParserImpl.h

 // 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.
 
 #ifndef CSSParserImpl_h
 #define CSSParserImpl_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/css/CSSProperty.h"
 #include "core/css/CSSPropertySourceData.h"
@@ skipping 95 matching lines @@
     void consumeDeclarationList(CSSParserTokenRange, StyleRule::RuleType);
     void consumeDeclaration(CSSParserTokenRange, StyleRule::RuleType);
     void consumeDeclarationValue(CSSParserTokenRange, CSSPropertyID, bool important, StyleRule::RuleType);
     void consumeVariableValue(CSSParserTokenRange, const AtomicString& propertyName, bool important);
 
     static PassOwnPtr<Vector<double>> consumeKeyframeKeyList(CSSParserTokenRange);
 
     // FIXME: Can we build StylePropertySets directly?
     // FIXME: Investigate using a smaller inline buffer
     HeapVector<CSSProperty, 256> m_parsedProperties;
-    CSSParserContext m_context;
+    const CSSParserContext& m_context;
 
     Member<StyleSheetContents> m_styleSheet;
 
     // For the inspector
     CSSParserObserverWrapper* m_observerWrapper;
 };
 
 } // namespace blink
 
 #endif // CSSParserImpl_h