Issue 21377. Specify that navigation regions are sorted and implement it.

pkg/analysis_server/test/integration/integration_test_methods.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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Convenience methods for running integration tests
@@ skipping 503 matching lines @@
    * analysis.setSubscriptions request.
    *
    * Parameters
    *
    * file ( FilePath )
    *
    *   The file containing the navigation regions.
    *
    * regions ( List<NavigationRegion> )
    *
-   *   The navigation regions contained in the file. Each navigation region
-   *   represents a list of targets associated with some range. The lists will
-   *   usually contain a single target, but can contain more in the case of a
-   *   part that is included in multiple libraries or in Dart code that is
-   *   compiled against multiple versions of a package. Note that the
-   *   navigation regions that are returned do not overlap other navigation
-   *   regions.
+   *   The navigation regions contained in the file. The regions are sorted by
+   *   their offsets. Each navigation region represents a list of targets
+   *   associated with some range. The lists will usually contain a single
+   *   target, but can contain more in the case of a part that is included in
+   *   multiple libraries or in Dart code that is compiled against multiple
+   *   versions of a package. Note that the navigation regions that are
+   *   returned do not overlap other navigation regions.
    */
   Stream<AnalysisNavigationParams> onAnalysisNavigation;
 
   /**
    * Stream controller for [onAnalysisNavigation].
    */
   StreamController<AnalysisNavigationParams> _onAnalysisNavigation;
 
   /**
    * Reports the occurrences of references to elements within a single file.
@@ skipping 801 matching lines @@
       case "execution.launchData":
         expect(params, isExecutionLaunchDataParams);
         _onExecutionLaunchData.add(new ExecutionLaunchDataParams.fromJson(decoder, 'params', params));
         break;
       default:
         fail('Unexpected notification: $event');
         break;
     }
   }
 }