Optimize functions on a second thread.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index e5d46cd903b8354d08391470d9f5d46564123d22..69ffc5e0dda41dbaf1b9c79c4540dad9181e5a51 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1493,7 +1493,8 @@ Isolate::Isolate()
       regexp_stack_(NULL),
       date_cache_(NULL),
       context_exit_happened_(false),
-      deferred_handles_head_(NULL) {
+      deferred_handles_head_(NULL),
+      optimizing_compiler_thread_(this) {
   TRACE_ISOLATE(constructor);
 
   memset(isolate_addresses_, 0,
@@ -1574,6 +1575,8 @@ void Isolate::Deinit() {
   if (state_ == INITIALIZED) {
     TRACE_ISOLATE(deinit);
 
+    if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Stop();
+
     if (FLAG_hydrogen_stats) HStatistics::Instance()->Print();
 
     // We must stop the logger before we tear down other components.
@@ -1915,6 +1918,7 @@ bool Isolate::Init(Deserializer* des) {
 
   state_ = INITIALIZED;
   time_millis_at_init_ = OS::TimeCurrentMillis();
+  if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Start();
   return true;
 }