Add ClassEntity.library, MemberEntity.library and FunctionEntity.isExternal

pkg/compiler/lib/src/elements/common.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.
 
 /// Mixins that implement convenience methods on [Element] subclasses.
 
 library elements.common;
 
 import '../common/names.dart' show Identifiers, Names, Uris;
 import '../common_elements.dart' show CommonElements;
@@ skipping 593 matching lines @@
 }
 
 enum _FromEnvironmentState {
   NOT,
   BOOL,
   INT,
   STRING,
 }
 
 abstract class ConstructorElementCommon implements ConstructorElement {
+  LibraryElement get library;
+
   _FromEnvironmentState _fromEnvironmentState;
 
   _FromEnvironmentState get fromEnvironmentState {
     if (_fromEnvironmentState == null) {
       _fromEnvironmentState = _FromEnvironmentState.NOT;
       if (name == Identifiers.fromEnvironment && library.isDartCore) {
         switch (enclosingClass.name) {
           case 'bool':
             _fromEnvironmentState = _FromEnvironmentState.BOOL;
             break;
@@ skipping 22 matching lines @@
   @override
   bool get isBoolFromEnvironmentConstructor {
     return fromEnvironmentState == _FromEnvironmentState.BOOL;
   }
 
   @override
   bool get isStringFromEnvironmentConstructor {
     return fromEnvironmentState == _FromEnvironmentState.STRING;
   }
 }