Deprecate the generated AST library and clean up imports

pkg/analysis_server/lib/src/protocol_server.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 protocol.server;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/plugin/protocol/protocol_dart.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart'
     as engine;
+import 'package:analyzer/dart/ast/ast.dart' as engine;
+import 'package:analyzer/dart/ast/visitor.dart' as engine;
 import 'package:analyzer/dart/element/element.dart' as engine;
 import 'package:analyzer/dart/element/type.dart' as engine;
 import 'package:analyzer/source/error_processor.dart';
-import 'package:analyzer/src/generated/ast.dart' as engine;
+import 'package:analyzer/src/dart/ast/utilities.dart' as engine;
 import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/error.dart' as engine;
 import 'package:analyzer/src/generated/source.dart' as engine;
 import 'package:analyzer/src/generated/utilities_dart.dart' as engine;
 
 export 'package:analysis_server/plugin/protocol/protocol.dart';
 export 'package:analysis_server/plugin/protocol/protocol_dart.dart';
 
 /**
  * Returns a list of AnalysisErrors corresponding to the given list of Engine
@@ skipping 231 matching lines @@
     if (lineInfo != null) {
       engine.LineInfo_Location offsetLocation =
           lineInfo.getLocation(range.offset);
       startLine = offsetLocation.lineNumber;
       startColumn = offsetLocation.columnNumber;
     }
   }
   return new Location(
       source.fullName, range.offset, range.length, startLine, startColumn);
 }