Add AnalysisSession to analyzer

pkg/analyzer/lib/dart/analysis/results.dart

 // Copyright (c) 2017, 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 'package:analyzer/dart/analysis/session.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * The result of performing some kind of analysis on a single file. Every result
  * that implements this interface will also implement a sub-interface.
  *
  * Clients may not extend, implement or mix-in this class.
  */
 abstract class AnalysisResult {
   /**
    * The absolute and normalized path of the file that was analyzed.
    */
   String get path;
 
   /**
+   * Return the session used to compute this result.
+   */
+  AnalysisSession get session;
+
+  /**
    * The state of the results.
    */
   ResultState get state;
 
   /**
    * The absolute URI of the file that was analyzed.
    */
   Uri get uri;
 }
 
@@ skipping 108 matching lines @@
    * when given the path to the compilation unit represented by the [element].
    *
    * The signature is based on the APIs of the files of the library (including
    * the file itself), and the transitive closure of files imported and exported
    * by the library. If the signature of a file has not changed, then there have
    * been no changes that would cause any files that depend on it to need to be
    * re-analyzed.
    */
   String get signature;
 }