Have srcset respond to viewport changes

Source/core/css/parser/SizesCalcParser.cpp

Index: Source/core/css/parser/SizesCalcParser.cpp
diff --git a/Source/core/css/parser/SizesCalcParser.cpp b/Source/core/css/parser/SizesCalcParser.cpp
index f99688bb609de3bfc86a010742aa83edb0604c60..087339d5888af0cb6af89346e32db893861c055b 100644
--- a/Source/core/css/parser/SizesCalcParser.cpp
+++ b/Source/core/css/parser/SizesCalcParser.cpp
@@ -10,11 +10,12 @@
 
 namespace WebCore {
 
-bool SizesCalcParser::parse(MediaQueryTokenIterator start, MediaQueryTokenIterator end, PassRefPtr<MediaValues> mediaValues, unsigned& result)
+bool SizesCalcParser::parse(MediaQueryTokenIterator start, MediaQueryTokenIterator end, PassRefPtr<MediaValues> mediaValues, unsigned& result, bool& viewportDependant)
 {
     SizesCalcParser parser(mediaValues);
     if (!parser.calcToReversePolishNotation(start, end))
         return false;
+    viewportDependant = parser.viewportDependant();
     return parser.calculate(result);
 }
 
@@ -93,6 +94,8 @@ bool SizesCalcParser::calcToReversePolishNotation(MediaQueryTokenIterator start,
             appendNumber(*it);
             break;
         case DimensionToken:
+            if (CSSPrimitiveValue::isViewportPercentageLength(it->unitType()))
+                m_viewportDependant = true;
             if (!CSSPrimitiveValue::isLength(it->unitType()) || !appendLength(*it))
                 return false;
             break;