Revert "Delete support for source mirrors"

tests/compiler/dart2js/memory_compiler.dart

Index: tests/compiler/dart2js/memory_compiler.dart
diff --git a/tests/compiler/dart2js/memory_compiler.dart b/tests/compiler/dart2js/memory_compiler.dart
index 3712603dbc70da3142ad4e9f22c091e098a30ed8..fa69df7a99c519025c85fcc028ef31d73b1898ca 100644
--- a/tests/compiler/dart2js/memory_compiler.dart
+++ b/tests/compiler/dart2js/memory_compiler.dart
@@ -16,6 +16,8 @@ import 'package:compiler/compiler_new.dart' show
     PackagesDiscoveryProvider;
 import 'package:compiler/src/diagnostics/messages.dart' show
     Message;
+import 'package:compiler/src/mirrors/source_mirrors.dart';
+import 'package:compiler/src/mirrors/analyze.dart';
 import 'package:compiler/src/null_compiler_output.dart' show
     NullCompilerOutput;
 import 'package:compiler/src/library_loader.dart' show
@@ -257,3 +259,23 @@ DiagnosticHandler createDiagnosticHandler(DiagnosticHandler diagnosticHandler,
   }
   return handler;
 }
+
+Future<MirrorSystem> mirrorSystemFor(Map<String,String> memorySourceFiles,
+                                     {DiagnosticHandler diagnosticHandler,
+                                      List<String> options: const [],
+                                      bool showDiagnostics: true}) {
+  Uri libraryRoot = Uri.base.resolve('sdk/');
+  Uri packageRoot = Uri.base.resolve(Platform.packageRoot);
+
+  var provider = new MemorySourceFileProvider(memorySourceFiles);
+  var handler =
+      createDiagnosticHandler(diagnosticHandler, provider, showDiagnostics);
+
+  List<Uri> libraries = <Uri>[];
+  memorySourceFiles.forEach((String path, _) {
+    libraries.add(new Uri(scheme: 'memory', path: path));
+  });
+
+  return analyze(libraries, libraryRoot, packageRoot,
+                 provider, handler, options);
+}