Have srcset respond to viewport changes

Source/core/css/parser/SizesCalcParser.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 SizesCalcParser_h
 #define SizesCalcParser_h
 
 #include "core/css/MediaValues.h"
 #include "core/css/parser/MediaQueryToken.h"
 #include "wtf/text/WTFString.h"
@@ skipping 16 matching lines @@
         : value(numericValue)
         , isLength(length)
         , operation(0)
     {
     }
 };
 
 class SizesCalcParser {
 
 public:
-    static bool parse(MediaQueryTokenIterator start, MediaQueryTokenIterator end, PassRefPtr<MediaValues>, unsigned& result);
+    SizesCalcParser(MediaQueryTokenIterator start, MediaQueryTokenIterator end, PassRefPtr<MediaValues>);
+    bool viewportDependant() const { return m_viewportDependant; }
+    unsigned result();
+    bool isValid() const { return m_isValid; }
 
 private:
-    SizesCalcParser(PassRefPtr<MediaValues> mediaValues)
-        : m_mediaValues(mediaValues)
-    {
-    }
-
     bool calcToReversePolishNotation(MediaQueryTokenIterator start, MediaQueryTokenIterator end);
-    bool calculate(unsigned& result);
+    bool calculate();
     void appendNumber(const MediaQueryToken&);
     bool appendLength(const MediaQueryToken&);
     bool handleOperator(Vector<MediaQueryToken>& stack, const MediaQueryToken&);
     void appendOperator(const MediaQueryToken&);
 
     Vector<SizesCalcValue> m_valueList;
     RefPtr<MediaValues> m_mediaValues;
+    bool m_viewportDependant;
+    bool m_isValid;
+    unsigned m_result;
 };
 
 } // namespace blink
 
 #endif // SizesCalcParser_h