Change UnusedLocalElementsVerifier to AST visitor.

pkg/analyzer/lib/src/dart/analysis/driver.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:typed_data';
 
 import 'package:analyzer/context/context_root.dart';
 import 'package:analyzer/context/declared_variables.dart';
@@ skipping 67 matching lines @@
  * results are "eventually consistent" with the file system by simply calling
  * [changeFile] any time the contents of a file on the file system have changed.
  *
  *
  * TODO(scheglov) Clean up the list of implicitly analyzed files.
  */
 class AnalysisDriver implements AnalysisDriverGeneric {
   /**
    * The version of data format, should be incremented on every format change.
    */
-  static const int DATA_VERSION = 35;
+  static const int DATA_VERSION = 36;
 
   /**
    * The number of exception contexts allowed to write. Once this field is
    * zero, we stop writing any new exception contexts in this process.
    */
   static int allowedNumberOfContextsToWrite = 10;
 
   /**
    * The scheduler that schedules analysis work in this, and possibly other
    * analysis drivers.
@@ skipping 1964 matching lines @@
           libraryDeclarations.add(new TopLevelDeclarationInSource(
               file.source, declaration, isExported));
         }
       }
     }
 
     // We're not done yet.
     return false;
   }
 }