Don't track allocations in product mode.

runtime/vm/heap.cc

Index: runtime/vm/heap.cc
diff --git a/runtime/vm/heap.cc b/runtime/vm/heap.cc
index 21a4b460dc4599f081cf573d05ac3cf6565f9dbf..7bbaccf6e4cdc4b8a4bca730f775e9e34910d608 100644
--- a/runtime/vm/heap.cc
+++ b/runtime/vm/heap.cc
@@ -350,6 +350,7 @@ void Heap::EndOldSpaceGC() {
 }
 
 
+#ifndef PRODUCT
 void Heap::UpdateClassHeapStatsBeforeGC(Heap::Space space) {
   ClassTable* class_table = isolate()->class_table();
   if (space == kNew) {
@@ -358,6 +359,7 @@ void Heap::UpdateClassHeapStatsBeforeGC(Heap::Space space) {
     class_table->ResetCountersOld();
   }
 }
+#endif
 
 
 void Heap::CollectNewSpaceGarbage(Thread* thread,
@@ -369,9 +371,9 @@ void Heap::CollectNewSpaceGarbage(Thread* thread,
     RecordBeforeGC(kNew, reason);
     VMTagScope tagScope(thread, VMTag::kGCNewSpaceTagId);
     TIMELINE_FUNCTION_GC_DURATION(thread, "CollectNewGeneration");
-    UpdateClassHeapStatsBeforeGC(kNew);
+    NOT_IN_PRODUCT(UpdateClassHeapStatsBeforeGC(kNew));
     new_space_.Scavenge(invoke_api_callbacks);
-    isolate()->class_table()->UpdatePromoted();
+    NOT_IN_PRODUCT(isolate()->class_table()->UpdatePromoted());
     RecordAfterGC(kNew);
     PrintStats();
     NOT_IN_PRODUCT(PrintStatsToTimeline(&tds));
@@ -393,7 +395,7 @@ void Heap::CollectOldSpaceGarbage(Thread* thread,
     RecordBeforeGC(kOld, reason);
     VMTagScope tagScope(thread, VMTag::kGCOldSpaceTagId);
     TIMELINE_FUNCTION_GC_DURATION(thread, "CollectOldGeneration");
-    UpdateClassHeapStatsBeforeGC(kOld);
+    NOT_IN_PRODUCT(UpdateClassHeapStatsBeforeGC(kOld));
     old_space_.MarkSweep(invoke_api_callbacks);
     RecordAfterGC(kOld);
     PrintStats();