Deprecate the generated AST library and clean up imports

pkg/analysis_server/lib/src/services/completion/dart/uri_contributor.dart

 // Copyright (c) 2014, 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 services.completion.contributor.dart.importuri;
 
 import 'dart:async';
 import 'dart:core' hide Resource;
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/file_system/file_system.dart';
-import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:path/path.dart' show posix;
 import 'package:path/src/context.dart';
 
 import '../../../protocol_server.dart'
     show CompletionSuggestion, CompletionSuggestionKind;
 
 /**
  * A contributor for calculating uri suggestions
@@ skipping 163 matching lines @@
   }
 
   String _extractPartialUri(SimpleStringLiteral node) {
     if (request.offset < node.contentsOffset) {
       return null;
     }
     return node.literal.lexeme.substring(
         node.contentsOffset - node.offset, request.offset - node.offset);
   }
 }