Decouple root visitors from object visitors.

src/v8threads.h

 // 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.
 
 #ifndef V8_V8THREADS_H_
 #define V8_V8THREADS_H_
 
 #include "src/isolate.h"
 
 namespace v8 {
 namespace internal {
 
+class RootVisitor;
+class ThreadLocalTop;
 
 class ThreadState {
  public:
   // Returns NULL after the last one.
   ThreadState* Next();
 
   enum List {FREE_LIST, IN_USE_LIST};
 
   void LinkInto(List list);
   void Unlink();
@@ skipping 21 matching lines @@
   bool terminate_on_restore_;
   char* data_;
   ThreadState* next_;
   ThreadState* previous_;
 
   ThreadManager* thread_manager_;
 
   friend class ThreadManager;
 };
 
-
-// Defined in isolate.h.
-class ThreadLocalTop;
-
-
 class ThreadVisitor {
  public:
   // ThreadLocalTop may be only available during this call.
   virtual void VisitThread(Isolate* isolate, ThreadLocalTop* top) = 0;
 
  protected:
   virtual ~ThreadVisitor() {}
 };
 
-
 class ThreadManager {
  public:
   void Lock();
   void Unlock();
 
   void ArchiveThread();
   bool RestoreThread();
   void FreeThreadResources();
   bool IsArchived();
 
-  void Iterate(ObjectVisitor* v);
+  void Iterate(RootVisitor* v);
   void IterateArchivedThreads(ThreadVisitor* v);
   bool IsLockedByCurrentThread() {
     return mutex_owner_.Equals(ThreadId::Current());
   }
 
   ThreadId CurrentId();
 
   void TerminateExecution(ThreadId thread_id);
 
   // Iterate over in-use states.
@@ skipping 25 matching lines @@
 
   friend class Isolate;
   friend class ThreadState;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_V8THREADS_H_