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

Source/modules/webaudio/testing/InternalsWebAudio.h

Index: Source/modules/webaudio/testing/InternalsWebAudio.h
diff --git a/Source/modules/webaudio/testing/InternalsWebAudio.h b/Source/modules/webaudio/testing/InternalsWebAudio.h
index 9536a49d4e3c91189ded00bf8748a900e4100a60..e7accfffc940f21641a38f66df724166c25c08f5 100644
--- a/Source/modules/webaudio/testing/InternalsWebAudio.h
+++ b/Source/modules/webaudio/testing/InternalsWebAudio.h
@@ -5,11 +5,14 @@
 #ifndef InternalsWebAudio_h
 #define InternalsWebAudio_h
 
+#include "wtf/Allocator.h"
+
 namespace blink {
 
 class Internals;
 
 class InternalsWebAudio {
+    STATIC_ONLY(InternalsWebAudio);
 public:
     static unsigned audioHandlerCount(Internals&);
 };