[serializer] remove some dead code.

src/snapshot/serialize.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_SNAPSHOT_SERIALIZE_H_
 #define V8_SNAPSHOT_SERIALIZE_H_
 
 #include "src/address-map.h"
 #include "src/heap/heap.h"
 #include "src/objects.h"
@@ skipping 118 matching lines @@
 };
 
 
 // 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 {
  public:
   static void Iterate(Isolate* isolate, ObjectVisitor* visitor);
 
-  static int nop() { return kNop; }
-
   // No reservation for large object space necessary.
   static const int kNumberOfPreallocatedSpaces = LAST_PAGED_SPACE + 1;
   static const int kNumberOfSpaces = LAST_SPACE + 1;
 
  protected:
   static bool CanBeDeferred(HeapObject* o);
 
   // ---------- byte code range 0x00..0x7f ----------
   // Byte codes in this range represent Where, HowToCode and WhereToPoint.
   // Where the pointed-to object can be found:
@@ skipping 495 matching lines @@
   void VisitPointers(Object** start, Object** end) override;
 
   // Serialize the current state of the heap.  The order is:
   // 1) Strong references.
   // 2) Partial snapshot cache.
   // 3) Weak references (e.g. the string table).
   virtual void SerializeStrongReferences();
   void SerializeObject(HeapObject* o, HowToCode how_to_code,
                        WhereToPoint where_to_point, int skip) override;
   void SerializeWeakReferencesAndDeferred();
-  void Serialize() {
-    SerializeStrongReferences();
-    SerializeWeakReferencesAndDeferred();
-  }
 
  private:
   intptr_t root_index_wave_front_;
   DISALLOW_COPY_AND_ASSIGN(StartupSerializer);
 };
 
 
 class CodeSerializer : public Serializer {
  public:
   static ScriptData* Serialize(Isolate* isolate,
@@ skipping 137 matching lines @@
   static const int kNumCodeStubKeysOffset = kNumReservationsOffset + kInt32Size;
   static const int kPayloadLengthOffset = kNumCodeStubKeysOffset + kInt32Size;
   static const int kChecksum1Offset = kPayloadLengthOffset + kInt32Size;
   static const int kChecksum2Offset = kChecksum1Offset + kInt32Size;
   static const int kHeaderSize = kChecksum2Offset + kInt32Size;
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_SNAPSHOT_SERIALIZE_H_