Use entities in most of MirrorsData

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

 // Copyright (c) 2017, 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 dart2js.kernel.env;
 
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/clone.dart';
 import 'package:kernel/type_algebra.dart';
 
@@ skipping 128 matching lines @@
     for (ir.Member member in _setterMap.values) {
       if (member is ir.Procedure) {
         f(member);
       } else {
         // Skip fields; these are also in _memberMap.
       }
     }
   }
 }
 
+class LibraryData {
+  final ir.Library library;
+  Iterable<ConstantValue> _metadata;
+
+  LibraryData(this.library);
+
+  Iterable<ConstantValue> getMetadata(KernelToElementMapBase elementMap) {
+    return _metadata ??= elementMap.getMetadata(library.annotations);
+  }
+
+  LibraryData copy() {
+    return new LibraryData(library);
+  }
+}
+
 /// Environment for fast lookup of class members.
 class ClassEnv {
   final ir.Class cls;
   final bool isUnnamedMixinApplication;
 
   Map<String, ir.Member> _constructorMap;
   Map<String, ir.Member> _memberMap;
   Map<String, ir.Member> _setterMap;
 
   ClassEnv(this.cls)
@@ skipping 280 matching lines @@
       }
     }
     return _constant;
   }
 
   @override
   FieldData copy() {
     return new FieldData(node);
   }
 }