Support for overlay only files in Analysis Server with the new driver.

pkg/analysis_server/lib/src/single_context_manager.dart

 // Copyright (c) 2016, 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.single_context_manager;
 
 import 'dart:async';
 import 'dart:core';
 import 'dart:math' as math;
 
@@ skipping 129 matching lines @@
   AnalysisContext getContextFor(String path) {
     if (context == null) {
       return null;
     } else if (_isContainedIn(includedPaths, path)) {
       return context;
     }
     return null;
   }
 
   @override
+  AnalysisDriver getDriverFor(String path) {
+    return null;

[Paul Berry, 2016/12/12 21:11:37]

Would it be better to throw UnimplementedError like we do in the method below?

[scheglov, 2016/12/12 21:13:08]

It would.
Thank you.
Fixed.

+  }
+
+  @override
   List<AnalysisDriver> getDriversInAnalysisRoot(Folder analysisRoot) {
     throw new UnimplementedError(
         'Unexpected invocation of getDriversInAnalysisRoot in SingleContextManager');
   }
 
   @override
   bool isIgnored(String path) {
     return !_isContainedIn(includedPaths, path) || _isExcludedPath(path);
   }
 
@@ skipping 352 matching lines @@
   static List<Resource> _getChildrenSafe(Folder folder) {
     try {
       return folder.getChildren();
     } on FileSystemException {
       // The folder either doesn't exist or cannot be read.
       // Either way, there are no children.
       return const <Resource>[];
     }
   }
 }