Rename NavigationHolder to NavigationCollector.

pkg/analysis_server/test/plugin/set_analysis_domain_test.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 test.plugin.analysis_contributor;
 
 import 'dart:async';
 
 import 'package:analysis_server/analysis/analysis_domain.dart';
 import 'package:analysis_server/analysis/navigation/navigation_core.dart';
@@ skipping 75 matching lines @@
     expect(targetFiles.single, '/testLocation.dart');
   }
 }
 
 class TestNavigationContributor implements NavigationContributor {
   final SetAnalysisDomainTest test;
 
   TestNavigationContributor(this.test);
 
   @override
-  void computeNavigation(NavigationHolder holder, AnalysisContext context,
+  void computeNavigation(NavigationCollector collector, AnalysisContext context,
       Source source, int offset, int length) {
-    holder.addRegion(1, 5, ElementKind.CLASS,
+    collector.addRegion(1, 5, ElementKind.CLASS,
         new Location('/testLocation.dart', 1, 2, 3, 4));
   }
 }
 
 class TestSetAnalysisDomainPlugin implements Plugin {
   final SetAnalysisDomainTest test;
 
   TestSetAnalysisDomainPlugin(this.test);
 
   @override
@@ skipping 14 matching lines @@
       expect(result.context, isNotNull);
       expect(result.target, isNotNull);
       expect(result.value, isNotNull);
       Source source = result.target.source;
       test.parsedUnitFiles.add(source.fullName);
       domain.scheduleNotification(
           result.context, source, AnalysisService.NAVIGATION);
     });
   }
 }