[part 2] Make classes and structures in modules fast-allocated.

Source/modules/mediastream/URLMediaStream.h

Index: Source/modules/mediastream/URLMediaStream.h
diff --git a/Source/modules/mediastream/URLMediaStream.h b/Source/modules/mediastream/URLMediaStream.h
index 09c96523da07155157a24a07acb7e165f57f231d..8fe758d255779aabb78557c589e797c599196d86 100644
--- a/Source/modules/mediastream/URLMediaStream.h
+++ b/Source/modules/mediastream/URLMediaStream.h
@@ -31,6 +31,7 @@
 #ifndef URLMediaStream_h
 #define URLMediaStream_h
 
+#include "wtf/Allocator.h"
 #include "wtf/Forward.h"
 
 namespace blink {
@@ -39,6 +40,7 @@ class MediaStream;
 class ExecutionContext;
 
 class URLMediaStream {
+    STATIC_ONLY(URLMediaStream);
 public:
     static String createObjectURL(ExecutionContext*, MediaStream*);
 };