Ensure actual URIs are properly processed.

pkg/analyzer/lib/src/generated/source_io.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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.source.io;
 
 import 'dart:collection';
@@ skipping 442 matching lines @@
       relPath = path.substring(index + 1);
     }
     for (JavaFile packagesDirectory in _packagesDirectories) {
       JavaFile resolvedFile = new JavaFile.relative(packagesDirectory, path);
       if (resolvedFile.exists()) {
         JavaFile canonicalFile =
             getCanonicalFile(packagesDirectory, pkgName, relPath);
         if (_isSelfReference(packagesDirectory, canonicalFile)) {
           uri = canonicalFile.toURI();
         }
-        return new FileBasedSource(canonicalFile, uri);
+        return new FileBasedSource(
+            canonicalFile, actualUri != null ? actualUri : uri);
       }
     }
     return new FileBasedSource(
         getCanonicalFile(_packagesDirectories[0], pkgName, relPath),
         actualUri != null ? actualUri : uri);
   }
 
   @override
   Uri restoreAbsolute(Source source) {
     String sourcePath = source.fullName;
@@ skipping 81 matching lines @@
   }
 
   /**
    * Return `true` if the given URI is a `file` URI.
    *
    * @param uri the URI being tested
    * @return `true` if the given URI is a `file` URI
    */
   static bool isFileUri(Uri uri) => uri.scheme == FILE_SCHEME;
 }