Decouple root visitors from object visitors.

src/snapshot/serializer-common.h

 // Copyright 2016 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_SNAPSHOT_SERIALIZER_COMMON_H_
 #define V8_SNAPSHOT_SERIALIZER_COMMON_H_
 
 #include "src/address-map.h"
 #include "src/external-reference-table.h"
 #include "src/globals.h"
+#include "src/visitors.h"
 
 namespace v8 {
 namespace internal {
 
 class Isolate;
 
 class ExternalReferenceEncoder {
  public:
   explicit ExternalReferenceEncoder(Isolate* isolate);
 
@@ skipping 45 matching lines @@
   static const int kSizeMask = kSize - 1;
   HeapObject* circular_queue_[kSize];
   int index_;
 
   DISALLOW_COPY_AND_ASSIGN(HotObjectsList);
 };
 
 // The Serializer/Deserializer class is a common superclass for Serializer and
 // Deserializer which is used to store common constants and methods used by
 // both.
-class SerializerDeserializer : public ObjectVisitor {
+class SerializerDeserializer : public RootVisitor {
  public:
-  static void Iterate(Isolate* isolate, ObjectVisitor* visitor);
+  static void Iterate(Isolate* isolate, RootVisitor* visitor);
 
   // No reservation for large object space necessary.
   // We also handle map space differenly.
   STATIC_ASSERT(MAP_SPACE == CODE_SPACE + 1);
   static const int kNumberOfPreallocatedSpaces = CODE_SPACE + 1;
   static const int kNumberOfSpaces = LAST_SPACE + 1;
 
  protected:
   static bool CanBeDeferred(HeapObject* o);
 
@@ skipping 216 matching lines @@
   bool owns_data_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SerializedData);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_SNAPSHOT_SERIALIZER_COMMON_H_