Cleanup WebKit prefixed names for classes in css directory.

Source/core/css/CSSRegionRule.cpp

Index: Source/core/css/CSSRegionRule.cpp
diff --git a/Source/core/css/WebKitCSSRegionRule.cpp b/Source/core/css/CSSRegionRule.cpp
similarity index 88%
rename from Source/core/css/WebKitCSSRegionRule.cpp
rename to Source/core/css/CSSRegionRule.cpp
index 704c912adedd51b53d39a9736b10d02494025ca9..7a34ab1e8dd8a7e3e7ac55def5ba2621496271ab 100644
--- a/Source/core/css/WebKitCSSRegionRule.cpp
+++ b/Source/core/css/CSSRegionRule.cpp
@@ -30,23 +30,23 @@
 
 #include "config.h"
 
-#include "core/css/WebKitCSSRegionRule.h"
+#include "core/css/CSSRegionRule.h"
 
 #include "RuntimeEnabledFeatures.h"
 #include "core/css/CSSParser.h"
 #include "core/css/CSSRuleList.h"
 #include "core/css/StyleRule.h"
-#include <wtf/MemoryInstrumentationVector.h>
-#include <wtf/text/StringBuilder.h>
+#include "wtf/MemoryInstrumentationVector.h"
+#include "wtf/text/StringBuilder.h"
 
 namespace WebCore {
-WebKitCSSRegionRule::WebKitCSSRegionRule(StyleRuleRegion* regionRule, CSSStyleSheet* parent)
+CSSRegionRule::CSSRegionRule(StyleRuleRegion* regionRule, CSSStyleSheet* parent)
     : CSSGroupingRule(regionRule, parent)
 {
     ASSERT(RuntimeEnabledFeatures::cssRegionsEnabled());
 }
 
-String WebKitCSSRegionRule::cssText() const
+String CSSRegionRule::cssText() const
 {
     StringBuilder result;
     result.appendLiteral("@-webkit-region ");