[part 1] Make classes and structures in modules/ fast-allocated.

Source/modules/encryptedmedia/EncryptedMediaUtils.h

Index: Source/modules/encryptedmedia/EncryptedMediaUtils.h
diff --git a/Source/modules/encryptedmedia/EncryptedMediaUtils.h b/Source/modules/encryptedmedia/EncryptedMediaUtils.h
index fb7cbad1e690cec213184a496a8a9f06632754f4..64dc3369418f8279122c2c0057b127fe623312be 100644
--- a/Source/modules/encryptedmedia/EncryptedMediaUtils.h
+++ b/Source/modules/encryptedmedia/EncryptedMediaUtils.h
@@ -6,20 +6,19 @@
 #define EncryptedMediaUtils_h
 
 #include "public/platform/WebEncryptedMediaTypes.h"
+#include "wtf/Allocator.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class EncryptedMediaUtils {
+    STATIC_ONLY(EncryptedMediaUtils);
 public:
     static WebEncryptedMediaInitDataType convertToInitDataType(const String& initDataType);
     static String convertFromInitDataType(WebEncryptedMediaInitDataType);
 
     static WebEncryptedMediaSessionType convertToSessionType(const String& sessionType);
     static String convertFromSessionType(WebEncryptedMediaSessionType);
-
-private:
-    EncryptedMediaUtils();
 };
 
 } // namespace blink