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

pkg/analysis_server/lib/src/single_context_manager.dart

Index: pkg/analysis_server/lib/src/single_context_manager.dart
diff --git a/pkg/analysis_server/lib/src/single_context_manager.dart b/pkg/analysis_server/lib/src/single_context_manager.dart
index 5c28cae3f107194a03c863287b4d9dc613bd35ea..4588fea8dbf0a1719a68d83fda6e9af8fcfba1c9 100644
--- a/pkg/analysis_server/lib/src/single_context_manager.dart
+++ b/pkg/analysis_server/lib/src/single_context_manager.dart
@@ -147,6 +147,11 @@ class SingleContextManager implements ContextManager {
   }
 
   @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');