Implemented an averaging object histogram in the vm.

runtime/vm/dart.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/dart.h"
 
 #include "vm/code_observers.h"
 #include "vm/dart_api_state.h"
 #include "vm/dart_entry.h"
 #include "vm/flags.h"
@@ skipping 88 matching lines @@
 #endif
   // Create the read-only handles area.
   ASSERT(predefined_handles_ == NULL);
   predefined_handles_ = new ReadOnlyHandles();
   // Create the VM isolate and finish the VM initialization.
   ASSERT(thread_pool_ == NULL);
   thread_pool_ = new ThreadPool();
   {
     ASSERT(vm_isolate_ == NULL);
     ASSERT(Flags::Initialized());
-    vm_isolate_ = Isolate::Init("vm-isolate");
+    vm_isolate_ = Isolate::Init("vm-isolate", true);
     StackZone zone(vm_isolate_);
     HandleScope handle_scope(vm_isolate_);
     Heap::Init(vm_isolate_);
     ObjectStore::Init(vm_isolate_);
     Object::InitOnce();
     ArgumentsDescriptor::InitOnce();
     StubCode::InitOnce();
     Scanner::InitOnce();
     Symbols::InitOnce(vm_isolate_);
     Object::CreateInternalMetaData();
@@ skipping 104 matching lines @@
   return predefined_handles_->handles_.AllocateScopedHandle();
 }
 
 
 bool Dart::IsReadOnlyHandle(uword address) {
   ASSERT(predefined_handles_ != NULL);
   return predefined_handles_->handles_.IsValidScopedHandle(address);
 }
 
 }  // namespace dart