Decouple root visitors from object visitors.

src/builtins/builtins.h

 // Copyright 2011 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.
 
 #ifndef V8_BUILTINS_BUILTINS_H_
 #define V8_BUILTINS_BUILTINS_H_
 
 #include "src/base/flags.h"
 #include "src/builtins/builtins-definitions.h"
 #include "src/globals.h"
 
 namespace v8 {
 namespace internal {
 
 class Callable;
 template <typename T>
 class Handle;
 class Isolate;
 
 // Forward declarations.
-class ObjectVisitor;
+class RootVisitor;
 enum class InterpreterPushArgsMode : unsigned;
 namespace compiler {
 class CodeAssemblerState;
 }
 
 class Builtins {
  public:
   ~Builtins();
 
   void TearDown();
 
   // Garbage collection support.
-  void IterateBuiltins(ObjectVisitor* v);
+  void IterateBuiltins(RootVisitor* v);
 
   // Disassembler support.
   const char* Lookup(byte* pc);
 
   enum Name : int32_t {
 #define DEF_ENUM(Name, ...) k##Name,
     BUILTIN_LIST_ALL(DEF_ENUM)
 #undef DEF_ENUM
         builtin_count
   };
@@ skipping 104 matching lines @@
   friend class Isolate;
   friend class SetupIsolateDelegate;
 
   DISALLOW_COPY_AND_ASSIGN(Builtins);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_BUILTINS_BUILTINS_H_