Give structured information about imports and export in the service's library response.

runtime/observatory/tests/service/get_object_rpc_test.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.
 // VMOptions=--compile-all --error_on_bad_type --error_on_bad_override
 
 library get_object_rpc_test;
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 107 matching lines @@
   (Isolate isolate) async {
     var params = {
       'objectId': isolate.rootLibrary.id,
     };
     var result = await isolate.invokeRpcNoUpgrade('getObject', params);
     expect(result['type'], equals('Library'));
     expect(result['id'], startsWith('libraries/'));
     expect(result['name'], equals('get_object_rpc_test'));
     expect(result['uri'], startsWith('file:'));
     expect(result['uri'], endsWith('get_object_rpc_test.dart'));
-    expect(result['imports'].length, isPositive);
-    expect(result['imports'][0]['type'], equals('@Library'));
+    expect(result['dependencies'].length, isPositive);
+    expect(result['dependencies'][0]['target']['type'], equals('@Library'));
     expect(result['scripts'].length, isPositive);
     expect(result['scripts'][0]['type'], equals('@Script'));
     expect(result['variables'].length, isPositive);
     expect(result['variables'][0]['type'], equals('@Field'));
     expect(result['functions'].length, isPositive);
     expect(result['functions'][0]['type'], equals('@Function'));
     expect(result['classes'].length, isPositive);
     expect(result['classes'][0]['type'], equals('@Class'));
   },
 
@@ skipping 275 matching lines @@
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kInvalidParams));
       expect(e.message,
              "getObject: invalid 'objectId' parameter: code/0");
     }
     expect(caughtException, isTrue);
   },
 ];
 
 main(args) async => runIsolateTests(args, tests, testeeBefore:warmup);