Make CSSParserMode parameter not optional for MutableStylePropertySet::create()

Source/core/css/DOMWindowCSS.cpp

Index: Source/core/css/DOMWindowCSS.cpp
diff --git a/Source/core/css/DOMWindowCSS.cpp b/Source/core/css/DOMWindowCSS.cpp
index ccb50f294fd3d671407d98152c94601fa81d32b6..1738ae6ce80e60ed19548900e05f6d4831ae6c52 100644
--- a/Source/core/css/DOMWindowCSS.cpp
+++ b/Source/core/css/DOMWindowCSS.cpp
@@ -49,7 +49,7 @@ bool DOMWindowCSS::supports(const String& property, const String& value)
     ASSERT(CSSPropertyMetadata::isEnabledProperty(unresolvedProperty));
 
     // This will return false when !important is present
-    RefPtrWillBeRawPtr<MutableStylePropertySet> dummyStyle = MutableStylePropertySet::create();
+    RefPtrWillBeRawPtr<MutableStylePropertySet> dummyStyle = MutableStylePropertySet::create(HTMLQuirksMode);
     return CSSParser::parseValue(dummyStyle.get(), unresolvedProperty, value, false, HTMLStandardMode, 0);
 }