Added option --script-snapshot in gen_snapshot to generate the snapshot of a scipt into the file.

runtime/bin/dartutils.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_DARTUTILS_H_
 #define BIN_DARTUTILS_H_
 
 #include "bin/builtin.h"
 #include "bin/utils.h"
 #include "include/dart_api.h"
@@ skipping 72 matching lines @@
   static bool IsDartCryptoLibURL(const char* url_name);
   static bool IsDartIOLibURL(const char* url_name);
   static bool IsDartJsonLibURL(const char* url_name);
   static bool IsDartUriLibURL(const char* url_name);
   static bool IsDartUtfLibURL(const char* url_name);
   static bool IsDartWebLibURL(const char* url_name);
   static Dart_Handle CanonicalizeURL(CommandLineOptions* url_mapping,
                                      Dart_Handle library,
                                      const char* url_str);
   static Dart_Handle ReadStringFromFile(const char* filename);
+  static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag,
+                                       Dart_Handle library,
+                                       Dart_Handle url);
+  static Dart_Handle LoadScript(const char* script_uri,
+                                bool resolve_script,
+                                Dart_Handle builtin_lib);
   static Dart_Handle LoadSource(CommandLineOptions* url_mapping,
                                 Dart_Handle library,
                                 Dart_Handle url,
                                 Dart_LibraryTag tag,
                                 const char* filename);
+  static Dart_Handle PrepareForScriptLoading(const char* package_root,
+                                             Dart_Handle builtin_lib);
+
   static bool PostNull(Dart_Port port_id);
   static bool PostInt32(Dart_Port port_id, int32_t value);
 
   // Create a new Dart OSError object with the current OS error.
   static Dart_Handle NewDartOSError();
   // Create a new Dart OSError object with the provided OS error.
   static Dart_Handle NewDartOSError(OSError* os_error);
 
+  static void SetOriginalWorkingDirectory();
+
+  // Global state that stores the original working directory..
+  static const char* original_working_directory;
+
   static const char* kDartScheme;
   static const char* kDartExtensionScheme;
   static const char* kBuiltinLibURL;
   static const char* kCoreLibURL;
   static const char* kCoreImplLibURL;
   static const char* kCryptoLibURL;
   static const char* kIOLibURL;
   static const char* kJsonLibURL;
   static const char* kUriLibURL;
   static const char* kUtfLibURL;
@@ skipping 233 matching lines @@
   void* Peer() const { return cobject_->value.as_external_byte_array.peer; }
   Dart_PeerFinalizer Callback() const {
     return cobject_->value.as_external_byte_array.callback;
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CObjectExternalUint8Array);
 };
 
 #endif  // BIN_DARTUTILS_H_