Register .analysis_options files for analysis.

pkg/analysis_server/lib/src/plugin/server_plugin.dart

 // Copyright (c) 2015, 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 analysis_server.src.plugin.server_plugin;
 
 import 'package:analysis_server/plugin/analysis/analysis_domain.dart';
 import 'package:analysis_server/plugin/analysis/analyzed_files.dart';
 import 'package:analysis_server/plugin/analysis/navigation/navigation.dart';
 import 'package:analysis_server/plugin/analysis/navigation/navigation_core.dart';
@@ skipping 253 matching lines @@
   }
 
   @override
   void registerExtensions(RegisterExtension registerExtension) {
     //
     // Register analyze file functions.
     //
     registerExtension(
         ANALYZE_FILE_EXTENSION_POINT_ID,
         (File file) => AnalysisEngine.isDartFileName(file.path) ||
-            AnalysisEngine.isHtmlFileName(file.path));
+            AnalysisEngine.isHtmlFileName(file.path) ||
+            AnalysisEngine.isAnalysisOptionsFileName(file.path));
     //
     // Register assist contributors.
     //
     registerExtension(
         ASSIST_CONTRIBUTOR_EXTENSION_POINT_ID, new DefaultAssistContributor());
     //
     // Register completion contributors.
     //
     // TODO(brianwilkerson) Register the completion contributors.
 //    registerExtension(COMPLETION_CONTRIBUTOR_EXTENSION_POINT_ID, ???);
@@ skipping 133 matching lines @@
    * valid analysis domain receiver.
    */
   void _validateSetAnalysisDomainFunction(Object extension) {
     if (extension is! SetAnalysisDomain) {
       String id = setAnalysisDomainExtensionPoint.uniqueIdentifier;
       throw new ExtensionError(
           'Extensions to $id must be a SetAnalysisDomain function');
     }
   }
 }