Change analysis server protocol to omit empty lists when optional.

pkg/analysis_server/test/analysis_abstract.dart

Index: pkg/analysis_server/test/analysis_abstract.dart
diff --git a/pkg/analysis_server/test/analysis_abstract.dart b/pkg/analysis_server/test/analysis_abstract.dart
index d8d86808973ad36ad20a80a5882f4d80fd4237df..39771e2ceaee0e9055a7651e52efc2fa1990f9ad 100644
--- a/pkg/analysis_server/test/analysis_abstract.dart
+++ b/pkg/analysis_server/test/analysis_abstract.dart
@@ -94,8 +94,8 @@ class AbstractAnalysisTest {
    */
   void createProject() {
     resourceProvider.newFolder(projectPath);
-    Request request = new AnalysisSetAnalysisRootsParams([projectPath],
-        []).toRequest('0');
+    Request request = new AnalysisSetAnalysisRootsParams(
+        included: [projectPath]).toRequest('0');
     handleSuccessfulRequest(request);
   }