Introduce LibraryEntity

pkg/compiler/lib/src/kernel/kernel_visitor.dart

 // Copyright (c) 2016, 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.md file.
 
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/frontend/accessors.dart'
     show
         Accessor,
         IndexAccessor,
         NullAwarePropertyAccessor,
@@ skipping 279 matching lines @@
       // arguments of [supertype] corresponds to T, and the type variables of
       // its element correspond to S.
       type =
           type.subst(supertype.typeArguments, supertype.element.typeVariables);
     }
     return kernel.typeToIr(type);
   }
 
   // TODO(ahe): Hack. Fix dart2js instead.
   ir.Name nameToIrName(Name name) {
-    assert(!name.isPrivate ||
-        name.library.implementation == currentElement.library.implementation);
+    assert(!name.isPrivate || name.library == currentElement.library);
     return kernel.irName(name.text, currentElement);
   }
 
   List<ir.DartType> computeTypesFromTypes(NodeList nodes, {int expected}) {
     if (expected == null) {
       throw "[expected] is null";
     }
     List<ir.DartType> types = new List<ir.DartType>(expected);
     Iterator<Node> iterator = nodes?.iterator;
     for (int i = 0; i < expected; i++) {
@@ skipping 2545 matching lines @@
       : this(null, true, node, initializers);
 
   accept(ir.Visitor v) => throw "unsupported";
 
   visitChildren(ir.Visitor v) => throw "unsupported";
 
   String toString() {
     return "IrFunction($kind, $isConstructor, $node, $initializers)";
   }
 }