Add Scoped Context Info (Isolate) to V8 Traces

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"
 #include "src/objects-inl.h"
@@ skipping 20 matching lines @@
 
 void Logger::CallEventLogger(Isolate* isolate, const char* name, StartEnd se,
                              bool expose_to_api) {
   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);
     }
   }
+
+  // We make 2 different macro calls instead of precalculating the category
+  // name because the category enabled status is cached based on its line no.
   if (expose_to_api) {
     if (se == START) {
       TRACE_EVENT_BEGIN0("v8", name);
     } else {
       TRACE_EVENT_END0("v8", name);
     }
   } else {
     if (se == START) {
       TRACE_EVENT_BEGIN0(TRACE_DISABLED_BY_DEFAULT("v8"), name);
     } else {
       TRACE_EVENT_END0(TRACE_DISABLED_BY_DEFAULT("v8"), name);
     }
   }
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_LOG_INL_H_