Support symbolic links and package imports in gen_snapshot.

runtime/bin/dartutils.h

Index: runtime/bin/dartutils.h
diff --git a/runtime/bin/dartutils.h b/runtime/bin/dartutils.h
index 76668ae7c35cf5328d3c5df582a2735ca01ab2b8..5ad0b9f54310dd182835457fda6732f81807a83f 100644
--- a/runtime/bin/dartutils.h
+++ b/runtime/bin/dartutils.h
@@ -144,6 +144,19 @@ class DartUtils {
 
   static void SetOriginalWorkingDirectory();
 
+  static const char* MapLibraryUrl(CommandLineOptions* url_mapping,
+                                   const char* url_string);
+
+  static Dart_Handle ResolveScriptUri(Dart_Handle script_uri,
+                                      Dart_Handle builtin_lib);
+
+  static Dart_Handle FilePathFromUri(Dart_Handle script_uri,
+                                     Dart_Handle builtin_lib);
+
+  static Dart_Handle ResolveUri(Dart_Handle library_url,
+                                Dart_Handle url,
+                                Dart_Handle builtin_lib);
+
   // Global state that stores the original working directory..
   static const char* original_working_directory;