Have srcset respond to viewport changes

Source/core/css/parser/SizesCalcParser.cpp

 // 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.
 
 #include "config.h"
 #include "core/css/parser/SizesCalcParser.h"
 
 #include "core/css/MediaValues.h"
 #include "core/css/parser/MediaQueryToken.h"
 
 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();

[esprehn, 2014/07/14 08:39:49]

ditto, make a real API.

     return parser.calculate(result);
 }
 
 static bool operatorPriority(UChar cc, bool& highPriority)
 {
     if (cc == '+' || cc == '-')
         highPriority = false;
     else if (cc == '*' || cc == '/')
         highPriority = true;
     else
@@ skipping 58 matching lines @@
     // http://en.wikipedia.org/wiki/Shunting-yard_algorithm
 
     Vector<MediaQueryToken> stack;
     for (MediaQueryTokenIterator it = start; it != end; ++it) {
         MediaQueryTokenType type = it->type();
         switch (type) {
         case NumberToken:
             appendNumber(*it);
             break;
         case DimensionToken:
+            if (CSSPrimitiveValue::isViewportPercentageLength(it->unitType()))

[esprehn, 2014/07/14 08:39:49]

Does this happen repeatedly? Should you be doing m_viewportDependant =
m_viewportDependant ||
CSSPrimitiveValue::isViewportPercentageLength(it->unitType()) instead?

It seems you're iterating here and doing duplicate work.

+                m_viewportDependant = true;
             if (!CSSPrimitiveValue::isLength(it->unitType()) || !appendLength(*it))
                 return false;
             break;
         case DelimiterToken:
             if (!handleOperator(stack, *it))
                 return false;
             break;
         case FunctionToken:
             if (it->value() != "calc")
                 return false;
@@ skipping 99 matching lines @@
         }
     }
     if (stack.size() == 1 && stack.last().isLength) {
         result = clampTo<unsigned>(stack.last().value);
         return true;
     }
     return false;
 }
 
 } // namespace WebCore