First pass at asynchronous input loading in dart2js.

sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart

Index: sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart
diff --git a/sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart b/sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart
index 74b6e563cecf2cd92e920fee162354ec0622522d..2ebc1e54b87813106c3ed33bfb7af7b0d9542e59 100644
--- a/sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart
+++ b/sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart
@@ -227,12 +227,13 @@ Future<MirrorSystem> analyze(List<Uri> libraries,
                                            internalDiagnosticHandler,
                                            libraryRoot, packageRoot, options);
   compiler.librariesToAnalyzeWhenRun = libraries;
-  bool success = compiler.run(null);
-  if (success && !compilationFailed) {
-    return new Future<MirrorSystem>.value(new Dart2JsMirrorSystem(compiler));
-  } else {
-    return new Future<MirrorSystem>.error('Failed to create mirror system.');
-  }
+  return compiler.run(null).then((bool success) {
+    if (success && !compilationFailed) {
+      return new Dart2JsMirrorSystem(compiler);
+    } else {
+      throw 'Failed to create mirror system.';

[ahe, 2013/09/02 13:43:24]

throw new StateError or something.

[Johnni Winther, 2013/09/03 07:51:39]

Done.

+    }
+  });
 }
 
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