Add sharedfrontend package

pkg/compiler/lib/src/elements/elements.dart

 // Copyright (c) 2012, 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.
 
-library elements;
+library dart2js.elements;
 
+import 'package:sharedfrontend/elements.dart' as shared;
 
 import '../constants/expressions.dart';
 import '../tree/tree.dart';
 import '../util/util.dart';
 import '../resolution/resolution.dart';
 
 import '../dart2jslib.dart' show InterfaceType,
                                  DartType,
                                  TypeVariableType,
                                  TypedefType,
@@ skipping 158 matching lines @@
  * code generation.
  *
  * The front-end data structures are designed to be reusable by
  * several back-ends.  For example, we may want to support emitting
  * minified Dart and JavaScript code in one go.  Also, we're planning
  * on adding an incremental compilation server that should be able to
  * reuse elements between compilations.  So to keep things simple, it
  * is best if the backends avoid setting state directly in elements.
  * It is better to keep such state in a table on the side.
  */
-abstract class Element implements Entity {
+abstract class Element implements shared.Element, Entity {
   String get name;
   ElementKind get kind;
   Element get enclosingElement;
   Link<MetadataAnnotation> get metadata;
 
   /// Do not use [computeType] outside of the resolver; instead retrieve the
   /// type from the corresponding field:
   /// - `type` for fields, variables, type variable, and function elements.
   /// - `thisType` or `rawType` for [TypeDeclarationElement]s (classes and
   ///    typedefs), depending on the use case.
@@ skipping 644 matching lines @@
 
   void forEachLocalMember(f(Element element));
   void addMember(Element element, DiagnosticListener listener);
   void setPartOf(PartOf tag, DiagnosticListener listener);
   bool get hasMembers;
 
   int compareTo(CompilationUnitElement other);
 }
 
 abstract class LibraryElement extends Element
-    implements ScopeContainerElement, AnalyzableElement {
+    implements ScopeContainerElement, AnalyzableElement, shared.LibraryElement {
   /**
    * The canonical uri for this library.
    *
    * For user libraries the canonical uri is the script uri. For platform
    * libraries the canonical uri is of the form [:dart:x:].
    */
   Uri get canonicalUri;
 
   /// Returns `true` if this library is 'dart:core'.
   bool get isDartCore;
@@ skipping 435 matching lines @@
   List<DartType> get typeVariables;
 
   bool get isResolved;
 
   int get resolutionState;
 
   void ensureResolved(Compiler compiler);
 }
 
 abstract class ClassElement extends TypeDeclarationElement
-    implements ScopeContainerElement {
+    implements ScopeContainerElement, shared.ClassElement {
   int get id;
 
   /// The length of the longest inheritance path from [:Object:].
   int get hierarchyDepth;
 
   InterfaceType get rawType;
   InterfaceType get thisType;
   ClassElement get superclass;
 
   /// The direct supertype of this class.
@@ skipping 304 matching lines @@
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }