Support external startup data in V8.

src/snapshot.h

Index: src/snapshot.h
diff --git a/src/snapshot.h b/src/snapshot.h
index d5271b2dac78537893ad61fd1c74e009761e66c5..a31a426ef0b177844f374e58458e36c762ee6730 100644
--- a/src/snapshot.h
+++ b/src/snapshot.h
@@ -12,10 +12,9 @@ namespace internal {
 
 class Snapshot {
  public:
-  // Initialize the VM from the given snapshot file. If snapshot_file is
-  // NULL, use the internal snapshot instead. Returns false if no snapshot
+  // Initialize the VM from the internal snapshot. Returns false if no snapshot
   // could be found.
-  static bool Initialize(const char* snapshot_file = NULL);
+  static bool Initialize();
 
   static bool HaveASnapshotToStartFrom();
 
@@ -23,12 +22,9 @@ class Snapshot {
   static Handle<Context> NewContextFromSnapshot(Isolate* isolate);
 
   // Returns whether or not the snapshot is enabled.
-  static bool IsEnabled() { return size_ != 0; }
-
-  // Write snapshot to the given file. Returns true if snapshot was written
-  // successfully.
-  static bool WriteToFile(const char* snapshot_file);
+  static bool IsEnabled();
 
+  // These methods support COMPRESS_STARTUP_DATA_BZ2.
   static const byte* data() { return data_; }
   static int size() { return size_; }
   static int raw_size() { return raw_size_; }
@@ -72,6 +68,10 @@ class Snapshot {
   DISALLOW_IMPLICIT_CONSTRUCTORS(Snapshot);
 };
 
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+void SetSnapshotFromFile(StartupData* snapshot_blob);
+#endif
+
 } }  // namespace v8::internal
 
 #endif  // V8_SNAPSHOT_H_