Use SizesAttributeParser to get the right srcset resource

Source/core/css/parser/SizesAttributeParser.cpp

Index: Source/core/css/parser/SizesAttributeParser.cpp
diff --git a/Source/core/css/parser/SizesAttributeParser.cpp b/Source/core/css/parser/SizesAttributeParser.cpp
index 4fd32365b7f52f793a534c9e60553c2585ab4ed0..d31b2c1a3d156f2dceef304894a720fc2c25bb6a 100644
--- a/Source/core/css/parser/SizesAttributeParser.cpp
+++ b/Source/core/css/parser/SizesAttributeParser.cpp
@@ -35,8 +35,7 @@ bool SizesAttributeParser::calculateLengthInPixels(TokenIterator startToken, Tok
                 return true;
             }
         }
-    }
-    if (type == FunctionToken) {
+    } else if (type == FunctionToken) {

[eseidel, 2014/04/20 21:27:43]

This change has no effect, but OK.  If the earlier places use "return" there is
no need for an "else" after returns.

         // FIXME - Handle calc() functions here!
     }
     return false;
@@ -101,6 +100,8 @@ bool SizesAttributeParser::parseMediaConditionAndLength(TokenIterator startToken
 
 bool SizesAttributeParser::parse(Vector<MediaQueryToken>& tokens)
 {
+    if (tokens.isEmpty())
+        return false;
     TokenIterator startToken = tokens.begin();
     TokenIterator endToken;
     // Split on a comma token, and send the result tokens to be parsed as (media-condition, length) pairs