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

pkg/compiler/lib/src/js_backend/lookup_map_analysis.dart

 // Copyright (c) 2015, 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.
 
 /// Analysis to determine how to generate code for `LookupMap`s.
 library compiler.src.js_backend.lookup_map_analysis;
 
+import '../common.dart';
 import '../common/registry.dart' show Registry;
 import '../compiler.dart' show Compiler;
-import '../diagnostics/diagnostic_listener.dart' show
-    DiagnosticReporter;
-import '../diagnostics/messages.dart' show
-    MessageKind;
 import '../constants/values.dart' show
     ConstantValue,
     ConstructedConstantValue,
     ListConstantValue,
     NullConstantValue,
     StringConstantValue,
     TypeConstantValue;
 import '../dart_types.dart' show DartType;
 import '../elements/elements.dart' show
     ClassElement,
@@ skipping 413 matching lines @@
       }
     } else {
       original.fields[analysis.entriesField] =
           new ListConstantValue(listType, keyValuePairs);
     }
   }
 }
 
 final _validLookupMapVersionConstraint =
     new VersionConstraint.parse('^0.0.1');