Sketch of on demand snapshot generation for d8

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index d4e76f5c76f54607809dcec3b67c4915289110fe..b221950a35cfd6531b36dcbb383eb22f63cd2d60 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -5330,6 +5330,21 @@ class V8_EXPORT V8 {
   static void SetNativesDataBlob(StartupData* startup_blob);
   static void SetSnapshotDataBlob(StartupData* startup_blob);
 
+  static void CreateV8Snapshot(const char* raw_file,
+                                const char* raw_context_file,
+                                const char* startup_blob,
+                                const char* extra_code,
+                                const char* out_file);
+
+  static void CreateSnapshotFromHeap(Isolate* isolate,
+                                     const char* raw_file,
+                                     const char* raw_context_file,
+                                     const char* startup_blob,
+                                     const char* extra_code,
+                                     const char* out_file);
+  static void SetFlags(bool harmony, int random_seed, bool probe);
+  static void SetLogFilePerIsolate(bool logfile);
+
   /**
    * Adds a message listener.
    *