Introduce code serializer/deserializer.

src/snapshot-source-sink.cc

Index: src/snapshot-source-sink.cc
diff --git a/src/snapshot-source-sink.cc b/src/snapshot-source-sink.cc
index 146f949cc476f44cc18f3ecca5dc7638506a565a..e9988eb7d3bb6ea24062182631befbb3b36327ad 100644
--- a/src/snapshot-source-sink.cc
+++ b/src/snapshot-source-sink.cc
@@ -91,5 +91,11 @@ bool SnapshotByteSource::GetBlob(const byte** data, int* number_of_bytes) {
   }
 }
 
+
+void DebugSnapshotSink::Put(int byte, const char* description) {
+  PrintF("%24s: %x\n", description, byte);
+  sink_->Put(byte, description);
+}
+
 }  // namespace v8::internal
 }  // namespace v8