Add support for allowing an embedder to get the V8 profile timer event logs.

src/isolate.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1998 matching lines @@
   if (create_heap_objects) {
     // Terminate the cache array with the sentinel so we can iterate.
     PushToPartialSnapshotCache(heap_.undefined_value());
   }
 
   InitializeThreadLocal();
 
   bootstrapper_->Initialize(create_heap_objects);
   builtins_.SetUp(this, create_heap_objects);
 
+  if (!event_logger_ && FLAG_log_internal_timer_events) {

[Yang, 2014/03/07 08:48:42]

I don't think we need to check for !event_logger_.

+    set_event_logger(Logger::LogInternalEvents);
+  } else {
+    set_event_logger(Logger::EmptyLogInternalEvents);
+  }
+
   // Set default value if not yet set.
   // TODO(yangguo): move this to ResourceConstraints::ConfigureDefaults
   // once ResourceConstraints becomes an argument to the Isolate constructor.
   if (max_available_threads_ < 1) {
     // Choose the default between 1 and 4.
     max_available_threads_ = Max(Min(CPU::NumberOfProcessorsOnline(), 4), 1);
   }
 
   if (!FLAG_job_based_sweeping) {
     num_sweeper_threads_ =
@@ skipping 294 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal