Make event logger slightly more light-weight.

src/log-inl.h

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_LOG_INL_H_
 #define V8_LOG_INL_H_
 
 #include "src/log.h"
 #include "src/isolate.h"
 
@@ skipping 11 matching lines @@
       default: return tag;
     }
   } else {
     return tag;
   }
 }
 
 
 void Logger::CallEventLogger(Isolate* isolate, const char* name, StartEnd se,
                              bool expose_to_api) {
-  if (isolate->event_logger() == NULL) {
-    if (FLAG_log_internal_timer_events) LOG(isolate, TimerEvent(se, name));
-  } else if (expose_to_api) {
-    isolate->event_logger()(name, se);
+  if (isolate->event_logger() != NULL) {
+    if (isolate->event_logger() == DefaultEventLoggerSentinel) {
+      LOG(isolate, TimerEvent(se, name));
+    } else if (expose_to_api) {
+      isolate->event_logger()(name, se);
+    }
   }
 }
 } }  // namespace v8::internal
 
 #endif  // V8_LOG_INL_H_