Ensure actual URIs are properly processed.

pkg/analyzer/lib/file_system/file_system.dart

Index: pkg/analyzer/lib/file_system/file_system.dart
diff --git a/pkg/analyzer/lib/file_system/file_system.dart b/pkg/analyzer/lib/file_system/file_system.dart
index 6005b5acf3586e52bffd81b1dcd28032b9f9b244..788600beac35d61483513eb558572c0a0cf36752 100644
--- a/pkg/analyzer/lib/file_system/file_system.dart
+++ b/pkg/analyzer/lib/file_system/file_system.dart
@@ -188,7 +188,7 @@ class ResourceUriResolver extends UriResolver {
     Resource resource =
         _provider.getResource(_provider.pathContext.fromUri(uri));
     if (resource is File) {
-      return resource.createSource(uri);
+      return resource.createSource(actualUri != null ? actualUri : uri);
     }
     return null;
   }