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 blink {
 
-bool SizesCalcParser::parse(MediaQueryTokenIterator start, MediaQueryTokenIterator end, PassRefPtr<MediaValues> mediaValues, unsigned& result)
+SizesCalcParser::SizesCalcParser(MediaQueryTokenIterator start, MediaQueryTokenIterator end, PassRefPtr<MediaValues> mediaValues)
+    : m_mediaValues(mediaValues)
+    , m_viewportDependant(false)
+    , m_result(0)
 {
-    SizesCalcParser parser(mediaValues);
-    if (!parser.calcToReversePolishNotation(start, end))
-        return false;
-    return parser.calculate(result);
+    m_isValid = calcToReversePolishNotation(start, end) && calculate();
+}
+
+unsigned SizesCalcParser::result() const
+{
+    ASSERT(m_isValid);
+    return m_result;
 }
 
 static bool operatorPriority(UChar cc, bool& highPriority)
 {
     if (cc == '+' || cc == '-')
         highPriority = false;
     else if (cc == '*' || cc == '/')
         highPriority = true;
     else
         return false;
@@ skipping 57 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:
+            m_viewportDependant = m_viewportDependant || CSSPrimitiveValue::isViewportPercentageLength(it->unitType());
             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 80 matching lines @@
         if (rightOperand.isLength || rightOperand.value == 0)
             return false;
         stack.append(SizesCalcValue(leftOperand.value / rightOperand.value, leftOperand.isLength));
         break;
     default:
         return false;
     }
     return true;
 }
 
-bool SizesCalcParser::calculate(unsigned& result)
+bool SizesCalcParser::calculate()
 {
     Vector<SizesCalcValue> stack;
     for (Vector<SizesCalcValue>::iterator it = m_valueList.begin(); it != m_valueList.end(); ++it) {
         if (it->operation == 0) {
             stack.append(*it);
         } else {
             if (!operateOnStack(stack, it->operation))
                 return false;
         }
     }
     if (stack.size() == 1 && stack.last().isLength) {
-        result = clampTo<unsigned>(stack.last().value);
+        m_result = clampTo<unsigned>(stack.last().value);
         return true;
     }
     return false;
 }
 
 } // namespace blink