Use common.dart to re-export commonly used entities.

pkg/compiler/lib/src/universe/side_effects.dart

Index: pkg/compiler/lib/src/universe/side_effects.dart
diff --git a/pkg/compiler/lib/src/universe/side_effects.dart b/pkg/compiler/lib/src/universe/side_effects.dart
index 4c5a719445c19b7a4fa60baf740c1a81af9d885f..f7625e40744f72cf1fe69ad97af733291a2d6017 100644
--- a/pkg/compiler/lib/src/universe/side_effects.dart
+++ b/pkg/compiler/lib/src/universe/side_effects.dart
@@ -4,29 +4,7 @@
 
 library universe.side_effects;
 
-import 'dart:collection';
-
-import '../common/names.dart' show
-    Identifiers,
-    Names,
-    Selectors;
-import '../compiler.dart' show
-    Compiler;
-import '../diagnostics/invariant.dart' show
-    invariant;
-import '../diagnostics/spannable.dart' show
-    SpannableAssertionFailure;
-import '../elements/elements.dart';
-import '../dart_types.dart';
-import '../tree/tree.dart';
-import '../types/types.dart';
-import '../util/util.dart';
-import '../world.dart' show
-    ClassWorld,
-    World;
-
-import 'selector.dart' show
-    Selector;
+import '../common.dart';
 
 class SideEffects {
   // Changes flags.