Move dart2jslib parts into separate libraries.

pkg/compiler/lib/src/mirrors/dart2js_mirrors.dart

Index: pkg/compiler/lib/src/mirrors/dart2js_mirrors.dart
diff --git a/pkg/compiler/lib/src/mirrors/dart2js_mirrors.dart b/pkg/compiler/lib/src/mirrors/dart2js_mirrors.dart
index 5bf4b1edf9dc33779b6ecbd125cb00477cfe8844..50435ed113d637b94418192c2416cfe725080657 100644
--- a/pkg/compiler/lib/src/mirrors/dart2js_mirrors.dart
+++ b/pkg/compiler/lib/src/mirrors/dart2js_mirrors.dart
@@ -8,15 +8,17 @@ import 'dart:collection' show UnmodifiableListView, UnmodifiableMapView;
 
 import '../constants/expressions.dart';
 import '../constants/values.dart';
-import '../elements/elements.dart';
-import '../scanner/scannerlib.dart';
-import '../resolution/resolution.dart' show Scope;
 import '../dart2jslib.dart';
 import '../dart_types.dart';
+import '../elements/elements.dart';
+import '../resolution/resolution.dart' show Scope;
+import '../scanner/scannerlib.dart';
+import '../script.dart';
 import '../tree/tree.dart';
 import '../util/util.dart'
     show Link,
-         LinkBuilder;
+         LinkBuilder,
+         NO_LOCATION_SPANNABLE;
 import '../util/characters.dart' show $CR, $LF;
 
 import 'source_mirrors.dart';