Use words please.

runtime/observatory/tests/service/debugging_test.dart

Index: runtime/observatory/tests/service/debugging_test.dart
diff --git a/runtime/observatory/tests/service/debugging_test.dart b/runtime/observatory/tests/service/debugging_test.dart
index a98702169656303aa3aea2a4d29b09a9e907a7f0..a4ce042f4bef98a74a08a4ed10fe945bcb87b8a2 100644
--- a/runtime/observatory/tests/service/debugging_test.dart
+++ b/runtime/observatory/tests/service/debugging_test.dart
@@ -55,7 +55,7 @@ var tests = [
 
 // Add breakpoint
 (Isolate isolate) async {
-  await isolate.rootLib.load();
+  await isolate.rootLibrary.load();
 
   // Set up a listener to wait for breakpoint events.
   Completer completer = new Completer();
@@ -68,7 +68,7 @@ var tests = [
     }
   });
 
-  var script = isolate.rootLib.scripts[0];
+  var script = isolate.rootLibrary.scripts[0];
   await script.load();
 
   // Add the breakpoint.
@@ -170,7 +170,7 @@ var tests = [
   });
 
   // Find a specific function.
-  ServiceFunction function = isolate.rootLib.functions.firstWhere(
+  ServiceFunction function = isolate.rootLibrary.functions.firstWhere(
       (f) => f.name == 'periodicTask');
   expect(function, isNotNull);