Postpone counters triggered during GC, and use a HandleScope when calling back.

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index ff6a11ee68740c536713a21a0d13ef42649b3080..58be0a23f3eba311852d616b4fcee8ae4c74f8ad 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -1311,6 +1311,8 @@ class Heap {
   // Returns minimal interval between two subsequent collections.
   double get_min_in_mutator() { return min_in_mutator_; }
 
+  void IncrementDeferredCount(v8::Isolate::UseCounterFeature feature);
+
   MarkCompactCollector* mark_compact_collector() {
     return &mark_compact_collector_;
   }
@@ -2047,6 +2049,8 @@ class Heap {
   // Total RegExp code ever generated
   double total_regexp_code_generated_;
 
+  int deferred_counters_[v8::Isolate::kUseCounterFeatureCount];
+
   GCTracer tracer_;
 
   // Creates and installs the full-sized number string cache.