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

Source/modules/mediastream/UserMediaClient.h

Index: Source/modules/mediastream/UserMediaClient.h
diff --git a/Source/modules/mediastream/UserMediaClient.h b/Source/modules/mediastream/UserMediaClient.h
index 9afa20b3e34fa3b5c22fb9119015897ab8bb013a..12e4af4f1d145d07247ed7c1a650950ae513c1a8 100644
--- a/Source/modules/mediastream/UserMediaClient.h
+++ b/Source/modules/mediastream/UserMediaClient.h
@@ -35,12 +35,14 @@
 #include "modules/mediastream/MediaDevicesRequest.h"
 #include "modules/mediastream/UserMediaRequest.h"
 #include "platform/mediastream/MediaStreamTrackSourcesRequest.h"
+#include "wtf/FastAllocBase.h"
 
 namespace blink {
 
 class LocalFrame;
 
 class UserMediaClient {
+    WTF_MAKE_FAST_ALLOCATED(UserMediaClient);
 public:
     virtual void requestUserMedia(UserMediaRequest*) = 0;
     virtual void cancelUserMediaRequest(UserMediaRequest*) = 0;