Using override keyword in ObjectVisitor class hierarchy.

src/heap/incremental-marking.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/gc-idle-time-handler.h"
@@ skipping 331 matching lines @@
   }
 };
 
 
 class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor {
  public:
   explicit IncrementalMarkingRootMarkingVisitor(
       IncrementalMarking* incremental_marking)
       : heap_(incremental_marking->heap()) {}
 
-  void VisitPointer(Object** p) { MarkObjectByPointer(p); }
+  void VisitPointer(Object** p) override { MarkObjectByPointer(p); }
 
-  void VisitPointers(Object** start, Object** end) {
+  void VisitPointers(Object** start, Object** end) override {
     for (Object** p = start; p < end; p++) MarkObjectByPointer(p);
   }
 
  private:
   void MarkObjectByPointer(Object** p) {
     Object* obj = *p;
     if (!obj->IsHeapObject()) return;
 
     IncrementalMarking::MarkObject(heap_, HeapObject::cast(obj));
   }
@@ skipping 786 matching lines @@
 void IncrementalMarking::IncrementIdleMarkingDelayCounter() {
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 }  // namespace internal
 }  // namespace v8