Integrate Chrome tracing with V8 (WIP)

src/log.cc

Index: src/log.cc
diff --git a/src/log.cc b/src/log.cc
index 3eede365b768ec51e42b1b5cf5180d3ea753265a..92cde1a8788fba0a8574b99ab065f5fc66806556 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -23,6 +23,7 @@
 #include "src/runtime-profiler.h"
 #include "src/serialize.h"
 #include "src/string-stream.h"
+#include "src/tracing/trace-event.h"
 #include "src/vm-state-inl.h"
 
 namespace v8 {
@@ -942,6 +943,8 @@ void Logger::TimerEvent(Logger::StartEnd se, const char* name) {
 
 
 void Logger::EnterExternal(Isolate* isolate) {
+  TRACE_EVENT_BEGIN0(TRACE_DISABLED_BY_DEFAULT("V8::External"),
+                     TimerEventExternal::name());
   LOG(isolate, TimerEvent(START, TimerEventExternal::name()));
   DCHECK(isolate->current_vm_state() == JS);
   isolate->set_current_vm_state(EXTERNAL);
@@ -949,6 +952,8 @@ void Logger::EnterExternal(Isolate* isolate) {
 
 
 void Logger::LeaveExternal(Isolate* isolate) {
+  TRACE_EVENT_END0(TRACE_DISABLED_BY_DEFAULT("V8::External"),
+                   TimerEventExternal::name());
   LOG(isolate, TimerEvent(END, TimerEventExternal::name()));
   DCHECK(isolate->current_vm_state() == EXTERNAL);
   isolate->set_current_vm_state(JS);
@@ -958,12 +963,12 @@ void Logger::LeaveExternal(Isolate* isolate) {
 template <class TimerEvent>
 void TimerEventScope<TimerEvent>::LogTimerEvent(Logger::StartEnd se) {
   Logger::CallEventLogger(isolate_, TimerEvent::name(), se,
-                          TimerEvent::expose_to_api());
+                          TimerEvent::overhead());
 }
 
 
 // Instantiate template methods.
-#define V(TimerName, expose)                                           \
+#define V(TimerName, overhead)                                         \
   template void TimerEventScope<TimerEvent##TimerName>::LogTimerEvent( \
       Logger::StartEnd se);
 TIMER_EVENTS_LIST(V)