[vm] Don't track allocation stats during marking in product mode.

runtime/vm/scavenger.cc

 // Copyright (c) 2011, 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/scavenger.h"
 
 #include "vm/dart.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
@@ skipping 55 matching lines @@
 class ScavengerVisitor : public ObjectPointerVisitor {
  public:
   explicit ScavengerVisitor(Isolate* isolate,
                             Scavenger* scavenger,
                             SemiSpace* from)
       : ObjectPointerVisitor(isolate),
         thread_(Thread::Current()),
         scavenger_(scavenger),
         from_(from),
         heap_(scavenger->heap_),
-        vm_heap_(Dart::vm_isolate()->heap()),
         page_space_(scavenger->heap_->old_space()),
         bytes_promoted_(0),
         visiting_old_object_(NULL) {}
 
   void VisitPointers(RawObject** first, RawObject** last) {
     if (FLAG_verify_gc_contains) {
       ASSERT((visiting_old_object_ != NULL) ||
              scavenger_->Contains(reinterpret_cast<uword>(first)) ||
              !heap_->Contains(reinterpret_cast<uword>(first)));
     }
@@ skipping 90 matching lines @@
     // Update the store buffer as needed.
     if (visiting_old_object_ != NULL) {
       UpdateStoreBuffer(p, new_obj);
     }
   }
 
   Thread* thread_;
   Scavenger* scavenger_;
   SemiSpace* from_;
   Heap* heap_;
-  Heap* vm_heap_;
   PageSpace* page_space_;
   RawWeakProperty* delayed_weak_properties_;
   intptr_t bytes_promoted_;
   RawObject* visiting_old_object_;
 
   friend class Scavenger;
 
   DISALLOW_COPY_AND_ASSIGN(ScavengerVisitor);
 };
 
@@ skipping 724 matching lines @@
   // Forces the next scavenge to promote all the objects in the new space.
   survivor_end_ = top_;
   Scavenge();
 
   // It is possible for objects to stay in the new space
   // if the VM cannot create more pages for these objects.
   ASSERT((UsedInWords() == 0) || failed_to_promote_);
 }
 
 }  // namespace dart