Have srcset respond to viewport changes

Source/core/css/parser/SizesAttributeParser.h

Index: Source/core/css/parser/SizesAttributeParser.h
diff --git a/Source/core/css/parser/SizesAttributeParser.h b/Source/core/css/parser/SizesAttributeParser.h
index 3c7bc4ee260c25283576e9169a1f6818161fe982..0365b707f648f8773bd7405110dd95115981cf7f 100644
--- a/Source/core/css/parser/SizesAttributeParser.h
+++ b/Source/core/css/parser/SizesAttributeParser.h
@@ -15,13 +15,14 @@ namespace WebCore {
 class SizesAttributeParser {
     STACK_ALLOCATED();
 public:
-    static unsigned findEffectiveSize(const String& attribute, PassRefPtr<MediaValues>);
+    static unsigned findEffectiveSize(const String& attribute, PassRefPtr<MediaValues>, bool& viewportDependant);
 
 private:
     SizesAttributeParser(PassRefPtr<MediaValues> mediaValues)
         : m_mediaValues(mediaValues)
         , m_length(0)
         , m_lengthWasSet(false)
+        , m_viewportDependant(false)
     {
     }
 
@@ -31,11 +32,13 @@ private:
     bool calculateLengthInPixels(MediaQueryTokenIterator startToken, MediaQueryTokenIterator endToken, unsigned& result);
     bool mediaConditionMatches(PassRefPtrWillBeRawPtr<MediaQuerySet> mediaCondition);
     unsigned effectiveSizeDefaultValue();
+    bool viewportDependant() const { return m_viewportDependant; }
 
     RefPtrWillBeMember<MediaQuerySet> m_mediaCondition;
     RefPtr<MediaValues> m_mediaValues;
     unsigned m_length;
     bool m_lengthWasSet;
+    bool m_viewportDependant;
 };
 
 } // namespace