Support percent encoded data URIs in the standalone embedder.

runtime/bin/builtin.dart

 // 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.
 
 library builtin;
 // NOTE: Do not import 'dart:io' in builtin.
 import 'dart:async';
 import 'dart:convert';
 import 'dart:isolate';
 
@@ skipping 197 matching lines @@
     return '$_DART_EXT${baseUri.resolve(uri)}';
   } else {
     return baseUri.resolve(userString).toString();
   }
 }
 
 Uri _createUri(String userUri) {
   var uri = Uri.parse(userUri);
   switch (uri.scheme) {
     case '':
+    case 'data':
     case 'file':
     case 'http':
     case 'https':
       return uri;
     case 'package':
       return _resolvePackageUri(uri);
     default:
       // Only handling file, http[s], and package URIs
       // in standalone binary.
       if (_logBuiltin) {
@@ skipping 114 matching lines @@
     _print('# Getting file path from: $uri');
   }
 
   var path;
   switch (uri.scheme) {
     case '':
     case 'file':
       return uri.toFilePath();
     case 'package':
       return _filePathFromUri(_resolvePackageUri(uri).toString());
+    case 'data':
     case 'http':
     case 'https':
       return uri.toString();
     default:
       // Only handling file, http, and package URIs
       // in standalone binary.
       if (_logBuiltin) {
         _print('# Unknown scheme (${uri.scheme}) in $uri.');
       }
       throw 'Not a known scheme: $uri';
@@ skipping 39 matching lines @@
   } else {
     name = userUri.substring(index + 1);
     path = userUri.substring(0, index + 1);
   }
 
   path = _filePathFromUri(path);
   var filename = _platformExtensionFileName(name);
 
   return [path, filename, name];
 }