Move CrossThreadCopier from platform/ to wtf/

third_party/WebKit/Source/core/css/MediaValuesCached.h

Index: third_party/WebKit/Source/core/css/MediaValuesCached.h
diff --git a/third_party/WebKit/Source/core/css/MediaValuesCached.h b/third_party/WebKit/Source/core/css/MediaValuesCached.h
index 8fddc5291847a3b620121c78c35729bc53de5a97..e351d4e7decb70673ef7d793dfa6141ce992cdaf 100644
--- a/third_party/WebKit/Source/core/css/MediaValuesCached.h
+++ b/third_party/WebKit/Source/core/css/MediaValuesCached.h
@@ -7,6 +7,7 @@
 
 #include "core/CoreExport.h"
 #include "core/css/MediaValues.h"
+#include "wtf/CrossThreadCopier.h"
 
 namespace blink {
 
@@ -110,12 +111,16 @@ protected:
     MediaValuesCachedData m_data;
 };
 
+} // namespace blink
+
+namespace WTF {
+
 template <>
-struct CrossThreadCopier<MediaValuesCached::MediaValuesCachedData> {
-    typedef MediaValuesCached::MediaValuesCachedData Type;
-    static Type copy(const MediaValuesCached::MediaValuesCachedData& data) { return data.deepCopy(); }
+struct CrossThreadCopier<blink::MediaValuesCached::MediaValuesCachedData> {
+    typedef blink::MediaValuesCached::MediaValuesCachedData Type;
+    static Type copy(const blink::MediaValuesCached::MediaValuesCachedData& data) { return data.deepCopy(); }
 };
 
-} // namespace blink
+} // namespace WTF
 
 #endif // MediaValuesCached_h