Decouple root visitors from object visitors.

src/bootstrapper.h

Index: src/bootstrapper.h
diff --git a/src/bootstrapper.h b/src/bootstrapper.h
index 9543897b3153f10ddde6964fa707f2cd6a77894b..315b70a119929851fb72f7fbcbe7f62cfb53b3a4 100644
--- a/src/bootstrapper.h
+++ b/src/bootstrapper.h
@@ -6,6 +6,7 @@
 #define V8_BOOTSTRAPPER_H_
 
 #include "src/factory.h"
+#include "src/visitors.h"
 
 namespace v8 {
 namespace internal {
@@ -23,8 +24,9 @@ class SourceCodeCache final BASE_EMBEDDED {
     cache_ = create_heap_objects ? isolate->heap()->empty_fixed_array() : NULL;
   }
 
-  void Iterate(ObjectVisitor* v) {
-    v->VisitPointer(bit_cast<Object**, FixedArray**>(&cache_));
+  void Iterate(RootVisitor* v) {
+    v->VisitRootPointer(Root::kExtensions,
+                        bit_cast<Object**, FixedArray**>(&cache_));
   }
 
   bool Lookup(Vector<const char> name, Handle<SharedFunctionInfo>* handle) {
@@ -93,7 +95,7 @@ class Bootstrapper final {
   void DetachGlobal(Handle<Context> env);
 
   // Traverses the pointers for memory management.
-  void Iterate(ObjectVisitor* v);
+  void Iterate(RootVisitor* v);
 
   // Accessor for the native scripts source code.
   template <class Source>