Remove redundant context lookups from option-processing code.

pkg/analysis_server/test/context_manager_test.dart

Index: pkg/analysis_server/test/context_manager_test.dart
diff --git a/pkg/analysis_server/test/context_manager_test.dart b/pkg/analysis_server/test/context_manager_test.dart
index 0b0d7ce5a6c23b2892516e51746baed67cff6204..08138585189b9ff37466e741c6299309bb1522ec 100644
--- a/pkg/analysis_server/test/context_manager_test.dart
+++ b/pkg/analysis_server/test/context_manager_test.dart
@@ -143,8 +143,9 @@ class AbstractContextManagerTest {
     manager.setRoots(<String>[projPath], <String>[], <String, String>{});
     expect(callbacks.currentContextFilePaths[projPath], isEmpty);
     // Set ignore patterns for context.
+    ContextInfo rootInfo = manager.getContextInfoFor(root);
     manager.setIgnorePatternsForContext(
-        root, ['sdk_ext/**', 'lib/ignoreme.dart']);
+        rootInfo, ['sdk_ext/**', 'lib/ignoreme.dart']);
     // Start creating files.
     newFile([projPath, ContextManagerImpl.PUBSPEC_NAME]);
     String libPath = newFolder([projPath, LIB_NAME]);