Move CompilerStats from isolate to thread. Aggregate stats.

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index a7ebef5168d9f886cb0a4b305129d39caf2fb466..22817d869bbd0abaf5d4fda1d02791227f2e72b7 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -776,7 +776,6 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       gc_epilogue_callback_(NULL),
       defer_finalization_count_(0),
       deopt_context_(NULL),
-      compiler_stats_(NULL),
       is_service_isolate_(false),
       stacktrace_(NULL),
       stack_frame_index_(-1),
@@ -846,10 +845,6 @@ Isolate::~Isolate() {
   boxed_field_list_mutex_ = NULL;
   ASSERT(spawn_count_ == 0);
   delete spawn_count_monitor_;
-  if (compiler_stats_ != NULL) {
-    delete compiler_stats_;
-    compiler_stats_ = NULL;
-  }
   delete safepoint_handler_;
   delete thread_registry_;
 }
@@ -923,13 +918,6 @@ Isolate* Isolate::Init(const char* name_prefix,
     }
   }
 
-  if (FLAG_support_compiler_stats) {
-    result->compiler_stats_ = new CompilerStats(result);
-    if (FLAG_compiler_benchmark) {
-      result->compiler_stats_->EnableBenchmark();
-    }
-  }
-
   if (FLAG_support_service) {
     ObjectIdRing::Init(result);
   }
@@ -1571,7 +1559,7 @@ void Isolate::Shutdown() {
     if (FLAG_support_compiler_stats && FLAG_compiler_stats
         && !ServiceIsolate::IsServiceIsolateDescendant(this)
         && (this != Dart::vm_isolate())) {
-      OS::Print("%s", compiler_stats()->PrintToZone());
+      OS::Print("%s", aggregate_compiler_stats()->PrintToZone());
     }
   }