Decouple root visitors from object visitors.

src/heap/object-stats.cc

Index: src/heap/object-stats.cc
diff --git a/src/heap/object-stats.cc b/src/heap/object-stats.cc
index e9067937aaffb541a01c302e8ed4c3404b2aa6ba..6a8dd26b70a1807b0d8f5d33dca11e0e33a037ee 100644
--- a/src/heap/object-stats.cc
+++ b/src/heap/object-stats.cc
@@ -271,13 +271,12 @@ void ObjectStatsCollector::CollectStatistics(HeapObject* obj) {
   if (obj->IsScript()) RecordScriptDetails(Script::cast(obj));
 }
 
-class ObjectStatsCollector::CompilationCacheTableVisitor
-    : public ObjectVisitor {
+class ObjectStatsCollector::CompilationCacheTableVisitor : public RootVisitor {
  public:
   explicit CompilationCacheTableVisitor(ObjectStatsCollector* parent)
       : parent_(parent) {}
 
-  void VisitPointers(Object** start, Object** end) override {
+  void VisitRootPointers(Root root, Object** start, Object** end) override {
     for (Object** current = start; current < end; current++) {
       HeapObject* obj = HeapObject::cast(*current);
       if (obj->IsUndefined(parent_->heap_->isolate())) continue;