Fix most implementations of UriResolver.restoreAbsolute.

pkg/analyzer/lib/file_system/file_system.dart

 // Copyright (c) 2014, 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 file_system;
 
 import 'dart:async';
 
 import 'package:analyzer/src/generated/source.dart';
 import 'package:path/path.dart';
@@ skipping 122 matching lines @@
  * [Resource]s.
  */
 abstract class ResourceProvider {
   /**
    * Get the path context used by this resource provider.
    */
   Context get pathContext;
 
   /**
    * Return a [File] that corresponds to the given [path].
-   * 
+   *
    * A file may or may not exist at this location.
    */
   File getFile(String path);
 
   /**
    * Return a [Folder] that corresponds to the given [path].
-   * 
+   *
    * A folder may or may not exist at this location.
    */
   Folder getFolder(String path);
 
   /**
    * Return the [Resource] that corresponds to the given [path].
    */
   Resource getResource(String path);
 
   /**
@@ skipping 26 matching lines @@
     }
     Resource resource =
         _provider.getResource(_provider.pathContext.fromUri(uri));
     if (resource is File) {
       return resource.createSource(actualUri != null ? actualUri : uri);
     }
     return null;
   }
 
   @override
-  Uri restoreAbsolute(Source source) => source.uri;
+  Uri restoreAbsolute(Source source) =>
+      _provider.pathContext.toUri(source.fullName);
 
   /**
    * Return `true` if the given [uri] is a `file` URI.
    */
   static bool _isFileUri(Uri uri) => uri.scheme == _FILE_SCHEME;
 }