New parser mode for CSSOM @viewport descriptors.

Source/core/css/CSSParser-in.cpp

Index: Source/core/css/CSSParser-in.cpp
diff --git a/Source/core/css/CSSParser-in.cpp b/Source/core/css/CSSParser-in.cpp
index 0e45c5c3823153039f0374dbb2109765b02dd9b1..ed175b9a0451f479df268df6d86e8328e1b67308 100644
--- a/Source/core/css/CSSParser-in.cpp
+++ b/Source/core/css/CSSParser-in.cpp
@@ -531,7 +531,7 @@ static bool parseSimpleLengthValue(MutableStylePropertySet* declaration, CSSProp
 {
     ASSERT(!string.isEmpty());
     bool acceptsNegativeNumbers;
-    if (!isSimpleLengthPropertyID(propertyId, acceptsNegativeNumbers))
+    if (cssParserMode == ViewportMode || !isSimpleLengthPropertyID(propertyId, acceptsNegativeNumbers))
         return false;
 
     unsigned length = string.length();
@@ -1196,8 +1196,14 @@ bool CSSParser::parseValue(MutableStylePropertySet* declaration, CSSPropertyID p
     m_id = propertyID;
     m_important = important;
 
+    if (declaration->cssParserMode() == ViewportMode)
+        markViewportRuleBodyStart();

[eseidel, 2013/09/10 16:33:58]

Bleh.  Do we need a helper function around cssyyparse?  Should this be a RAII?

These sort of paired state changes are always ugly and error-prone. This will
not scale well with a second such change.

[rune, 2013/09/12 13:05:01]

Did an RAII.

+
     cssyyparse(this);
 
+    if (declaration->cssParserMode() == ViewportMode)
+        markViewportRuleBodyEnd();
+
     m_rule = 0;
     m_id = CSSPropertyInvalid;
 
@@ -1311,7 +1317,15 @@ bool CSSParser::parseDeclaration(MutableStylePropertySet* declaration, const Str
         m_sourceDataHandler->endRuleHeader(1);
         m_sourceDataHandler->startRuleBody(0);
     }
+
+    if (declaration->cssParserMode() == ViewportMode)
+        markViewportRuleBodyStart();
+
     cssyyparse(this);
+
+    if (declaration->cssParserMode() == ViewportMode)
+        markViewportRuleBodyEnd();
+
     m_rule = 0;
 
     bool ok = false;
@@ -1378,7 +1392,9 @@ PassRefPtr<ImmutableStylePropertySet> CSSParser::createStylePropertySet()
     if (unusedEntries)
         results.remove(0, unusedEntries);
 
-    return ImmutableStylePropertySet::create(results.data(), results.size(), m_context.mode);
+    CSSParserMode mode = inViewport() ? ViewportMode : m_context.mode;
+
+    return ImmutableStylePropertySet::create(results.data(), results.size(), mode);
 }
 
 void CSSParser::addPropertyWithPrefixingVariant(CSSPropertyID propId, PassRefPtr<CSSValue> value, bool important, bool implicit)