Use summary IDL file for interface classes.

pkg/analyzer/test/src/summary/summary_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.
 
 library analyzer.test.src.summary.summary_common;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_engine_io.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/summary/base.dart';
-import 'package:analyzer/src/summary/format.dart';
+import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/public_namespace_computer.dart'
     as public_namespace;
 import 'package:analyzer/src/summary/summarize_elements.dart'
     as summarize_elements;
 import 'package:unittest/unittest.dart';
 
 import '../../generated/resolver_test.dart';
 
 /**
  * The public namespaces of the sdk are computed once so that we don't bog
@@ skipping 5232 matching lines @@
   final String absoluteUri;
   final String relativeUri;
   final int numTypeParameters;
 
   _PrefixExpectation(this.kind, this.name,
       {this.inLibraryDefiningUnit: false,
       this.absoluteUri,
       this.relativeUri,
       this.numTypeParameters: 0});
 }