Dart: Roll runtime forward

mojo/dart/embedder/builtin.dart

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 library mojo_builtin;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:mojo.internal';
 
 // Corelib 'print' implementation.
 void _print(arg) {
   _Logger._printString(arg.toString());
 }
 
 class _Logger {
   static void _printString(String s) native "Logger_PrintString";
 }
 
 String _rawUriBase;
 Uri _cachedUriBase;
 Uri _uriBase() {
   if (_cachedUriBase != null) {
     return _cachedUriBase;
   }
   _cachedUriBase = Uri.parse(_rawUriBase);
   return _cachedUriBase;
 }
 
+String _rawScript;
+Uri _scriptUri() {
+  if (_rawScript.startsWith('http:') ||
+      _rawScript.startsWith('https:') ||
+      _rawScript.startsWith('file:')) {
+    return Uri.parse(_rawScript);
+  } else {
+    return Uri.base.resolveUri(new Uri.file(_rawScript));
+  }
+}
+
 _setupHooks() {
   VMLibraryHooks.eventHandlerSendData = MojoHandleWatcher.timer;
   VMLibraryHooks.timerMillisecondClock = MojoCoreNatives.timerMillisecondClock;
+
+  // TODO(zra): When the Dart issue here:
+  // https://github.com/dart-lang/sdk/issues/25603
+  // is resolved, there will be no need to eagerly compute the script URI.
+  VMLibraryHooks.platformScript = _scriptUri();
 }
 
 _getUriBaseClosure() => _uriBase;
 _getPrintClosure() => _print;
 
 // import 'root_library'; happens here from C Code
 // The root library (aka the script) is imported into this library. The
 // embedder uses this to lookup the main entrypoint in the root library's
 // namespace.
-Function _getMainClosure() => main;
+Function _getMainClosure() => main;