Fix MQEvaluator::mediaType() related perf regressions.

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index e7c5ab5c58f4e042c2cee74d0b805b26102f3158..798dc9ddeef74967fe3c4968f8dc719ed1d00db6 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -31,6 +31,7 @@
 
 #include "core/CSSPropertyNames.h"
 #include "core/HTMLNames.h"
+#include "core/MediaTypeNames.h"
 #include "core/StylePropertyShorthand.h"
 #include "core/animation/ActiveAnimations.h"
 #include "core/animation/Animation.h"
@@ -467,12 +468,19 @@ void StyleResolver::matchWatchSelectorRules(ElementRuleCollector& collector)
     collector.sortAndTransferMatchedRules();
 }
 
+static bool printMediaType(FrameView* view)
+{
+    if (!view)
+        return false;
+    return equalIgnoringCase(view->mediaType(), MediaTypeNames::print);
+}
+
 void StyleResolver::matchUARules(ElementRuleCollector& collector)
 {
     collector.setMatchingUARules(true);
 
     CSSDefaultStyleSheets& defaultStyleSheets = CSSDefaultStyleSheets::instance();
-    RuleSet* userAgentStyleSheet = m_medium->mediaTypeMatchSpecific("print")
+    RuleSet* userAgentStyleSheet = printMediaType(document().view())

[esprehn, 2014/07/25 23:42:04]

Why would this be slow? mediaTypeMatchSpecific just compares the string right?

         ? defaultStyleSheets.defaultPrintStyle() : defaultStyleSheets.defaultStyle();
     matchUARules(collector, userAgentStyleSheet);