fixes needed to get smoke tests passing

pkg/smoke/test/codegen/testing_resolver_utils.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.
 
 /// Utility functions to test the code generation tools with the resolver.
 // Note, this is just for simple tests, so we restricted the logic to only
 // support root-relative imports. For more sophisticated stuff, you should be
 // using the test helpers in `package:code_transformers`.
 library smoke.test.codegen.testing_resolver_utils;
 
@@ skipping 44 matching lines @@
   Source resolveAbsolute(Uri uri) => allSources['$uri'];
 
   Source fromEncoding(UriKind kind, Uri uri) =>
       throw new UnimplementedError('fromEncoding not implemented');
 
   Uri restoreAbsolute(Source source) =>
       throw new UnimplementedError('restoreAbsolute not implemented');
 }
 
 class _SimpleSource extends Source {
+  final Uri uri;
   final String path;
   final String rawContents;
   final Map<String, Source> allSources;
 
-  _SimpleSource(this.path, this.rawContents, this.allSources);
+  _SimpleSource(this.path, this.rawContents, this.allSources)
+      : uri = Uri.parse('file:///path');
 
   operator ==(other) => other is _SimpleSource &&
       rawContents == other.rawContents;
   int get hashCode => rawContents.hashCode;
 
   bool exists() => true;
   String get encoding => '$uriKind/$path';
   String get fullName => path;
   TimestampedData<String> get contents =>
       new TimestampedData<String>(modificationStamp, rawContents);
 
   int get modificationStamp => 1;
   String get shortName => path;
   UriKind get uriKind => UriKind.FILE_URI;
   final bool isInSystemLibrary = false;
 
   // Since this is just for simple tests we just restricted this mock
   // to root-relative imports. For more sophisticated stuff, you should be
   // using the test helpers in `package:code_transformers`.
-  Source resolveRelative(Uri uri) {
-    if (uri.path.startsWith('/')) return allSources['${uri.path}'];
-    throw new UnimplementedError('relative URIs not supported: $uri');
+  Uri resolveRelative(Uri uri) {
+    if (!uri.path.startsWith('/')) {
+      throw new UnimplementedError('relative URIs not supported: $uri');
+    }
+    return uri;
   }
 
   void getContentsToReceiver(Source_ContentReceiver receiver) {
     receiver.accept(rawContents, modificationStamp);
   }
 }