Make event logger slightly more light-weight.

src/log.h

Index: src/log.h
diff --git a/src/log.h b/src/log.h
index 2bcd42f0d2be17d541920ca746e79befb50f647b..abf35f0ebc5ddcf0373f598d0cf48eee1d479e5c 100644
--- a/src/log.h
+++ b/src/log.h
@@ -300,8 +300,10 @@ class Logger {
   static void EnterExternal(Isolate* isolate);
   static void LeaveExternal(Isolate* isolate);
 
-  static inline void CallEventLogger(Isolate* isolate, const char* name,
-                                     StartEnd se, bool expose_to_api);
+  static void DefaultEventLoggerSentinel(const char* name, int event) {}
+
+  INLINE(static void CallEventLogger(Isolate* isolate, const char* name,
+                                     StartEnd se, bool expose_to_api));
 
   // ==== Events logged by --log-regexp ====
   // Regexp compilation and execution events.