Serialize external strings in the code serializer.

src/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_SERIALIZE_H_
 #define V8_SERIALIZE_H_
 
 #include "src/compiler.h"
 #include "src/hashmap.h"
 #include "src/heap-profiler.h"
@@ skipping 421 matching lines @@
     // Used for seralizing the external strings that hold the natives source.
     void VisitExternalOneByteString(
         v8::String::ExternalOneByteStringResource** resource);
     // We can't serialize a heap with external two byte strings.
     void VisitExternalTwoByteString(
         v8::String::ExternalStringResource** resource) {
       UNREACHABLE();
     }
 
    private:
+    void SerializePrologue(int space, int size, Map* map);
+
     enum ReturnSkip { kCanReturnSkipInsteadOfSkipping, kIgnoringReturn };
     // This function outputs or skips the raw data between the last pointer and
     // up to the current position.  It optionally can just return the number of
     // bytes to skip instead of performing a skip instruction, in case the skip
     // can be merged into the next instruction.
     int OutputRawData(Address up_to, ReturnSkip return_skip = kIgnoringReturn);
+    // External strings are serialized in a way to resemble sequential strings.
+    void SerializeExternalString();
 
     Serializer* serializer_;
     HeapObject* object_;
     SnapshotByteSink* sink_;
     int reference_representation_;
     int bytes_processed_so_far_;
     bool code_object_;
     bool code_has_been_output_;
   };
 
@@ skipping 245 matching lines @@
   // Following the header, we store, in sequential order
   // - code stub keys
   // - serialization payload
 
   ScriptData* script_data_;
   bool owns_script_data_;
 };
 } }  // namespace v8::internal
 
 #endif  // V8_SERIALIZE_H_