Make classes and structures in core/inspector fast-allocated.

Source/core/inspector/MainThreadDebugger.h

Index: Source/core/inspector/MainThreadDebugger.h
diff --git a/Source/core/inspector/MainThreadDebugger.h b/Source/core/inspector/MainThreadDebugger.h
index bb5cc3f7696f9c1e239fb92e40816fbe5a0bf088..203ad6d952a62c87e96aad151505b54cee0be038 100644
--- a/Source/core/inspector/MainThreadDebugger.h
+++ b/Source/core/inspector/MainThreadDebugger.h
@@ -49,6 +49,7 @@ class CORE_EXPORT MainThreadDebugger final : public ScriptDebuggerBase {
     WTF_MAKE_NONCOPYABLE(MainThreadDebugger);
 public:
     class ClientMessageLoop {
+        WTF_MAKE_FAST_ALLOCATED(ClientMessageLoop);
     public:
         virtual ~ClientMessageLoop() { }
         virtual void run(LocalFrame*) = 0;