Update the plugin API

pkg/analyzer_plugin/lib/src/utilities/navigation/navigation.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/results.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/source.dart' show SourceRange;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/utilities/navigation/navigation.dart';
 import 'package:analyzer_plugin/utilities/pair.dart';
 
 /**
+ * A concrete implementation of [DartNavigationRequest].
+ */
+class DartNavigationRequestImpl implements DartNavigationRequest {
+  @override
+  final ResourceProvider resourceProvider;
+
+  @override
+  final int length;
+
+  @override
+  final int offset;
+
+  @override
+  final ResolveResult result;
+
+  /**
+   * Initialize a newly create request with the given data.
+   */
+  DartNavigationRequestImpl(
+      this.resourceProvider, this.offset, this.length, this.result);
+
+  @override
+  String get path => result.path;
+}
+
+/**
  * A concrete implementation of [NavigationCollector].
  */
 class NavigationCollectorImpl implements NavigationCollector {
   /**
    * A list of navigation regions.
    */
   final List<NavigationRegion> regions = <NavigationRegion>[];
   final Map<SourceRange, List<int>> regionMap = <SourceRange, List<int>>{};
 
   /**
@@ skipping 53 matching lines @@
           location.offset,
           location.length,
           location.startLine,
           location.startColumn);
       targets.add(target);
       targetMap[pair] = index;
     }
     return index;
   }
 }
-
-/**
- * A concrete implementation of [NavigationRequest].
- */
-class NavigationRequestImpl implements NavigationRequest {
-  @override
-  final ResourceProvider resourceProvider;
-
-  @override
-  final int length;
-
-  @override
-  final int offset;
-
-  @override
-  final ResolveResult result;
-
-  /**
-   * Initialize a newly create request with the given data.
-   */
-  NavigationRequestImpl(
-      this.resourceProvider, this.offset, this.length, this.result);
-}