[serializer] introduce API to serialize internal fields

src/snapshot/deserializer.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_DESERIALIZER_H_
 #define V8_SNAPSHOT_DESERIALIZER_H_
 
 #include "src/heap/heap.h"
 #include "src/objects.h"
 #include "src/snapshot/serializer-common.h"
@@ skipping 70 matching lines @@
 
   void SetAlignment(byte data) {
     DCHECK_EQ(kWordAligned, next_alignment_);
     int alignment = data - (kAlignmentPrefix - 1);
     DCHECK_LE(kWordAligned, alignment);
     DCHECK_LE(alignment, kSimd128Unaligned);
     next_alignment_ = static_cast<AllocationAlignment>(alignment);
   }
 
   void DeserializeDeferredObjects();
+  void DeserializeInternalFields();
 
   void FlushICacheForNewIsolate();
   void FlushICacheForNewCodeObjectsAndRecordEmbeddedObjects();
 
   void CommitPostProcessedObjects(Isolate* isolate);
 
   // Fills in some heap data in an area from start to end (non-inclusive).  The
   // space id is used for the write barrier.  The object_address is the address
   // of the object we are writing into, or NULL if we are not writing into an
   // object, i.e. if we are writing a series of tagged values that are not on
@@ skipping 43 matching lines @@
 
   AllocationAlignment next_alignment_;
 
   DISALLOW_COPY_AND_ASSIGN(Deserializer);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_SNAPSHOT_DESERIALIZER_H_