Add support to pass the location of the analysis options file to plugins

pkg/analysis_server/test/src/plugin/plugin_manager_test.dart

Index: pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
diff --git a/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart b/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
index 47500578ed6d6792f33b51c67fbfe6b716e4340c..2fd7c361855ce5f9c71708753f9a9cd7a8c62ad4 100644
--- a/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
+++ b/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
@@ -119,11 +119,21 @@ class DiscoveredPluginInfoTest {
   }
 
   test_addContextRoot() {
+    String optionsFilePath = '/pkg1/analysis_options.yaml';
     ContextRoot contextRoot1 = new ContextRoot('/pkg1', []);
+    contextRoot1.optionsFilePath = optionsFilePath;
+    PluginSession session = new PluginSession(plugin);
+    TestServerCommunicationChannel channel =
+        new TestServerCommunicationChannel(session);
+    plugin.currentSession = session;
     plugin.addContextRoot(contextRoot1);
     expect(plugin.contextRoots, [contextRoot1]);
     plugin.addContextRoot(contextRoot1);
     expect(plugin.contextRoots, [contextRoot1]);
+    List<Request> sentRequests = channel.sentRequests;
+    expect(sentRequests, hasLength(1));
+    List<Map> roots = sentRequests[0].params['roots'];
+    expect(roots[0]['optionsFile'], optionsFilePath);
   }
 
   test_creation() {