Run dartfmt on all files under runtime.

runtime/observatory/tests/observatory_ui/persistent_handles_page/element_test.dart

Index: runtime/observatory/tests/observatory_ui/persistent_handles_page/element_test.dart
diff --git a/runtime/observatory/tests/observatory_ui/persistent_handles_page/element_test.dart b/runtime/observatory/tests/observatory_ui/persistent_handles_page/element_test.dart
index f2e4b848742a71698a3e0a7dca4bb750542e37ab..ff3f97ca0115e76054beb30f437eaa9b4b0ec4dc 100644
--- a/runtime/observatory/tests/observatory_ui/persistent_handles_page/element_test.dart
+++ b/runtime/observatory/tests/observatory_ui/persistent_handles_page/element_test.dart
@@ -17,21 +17,20 @@ main() {
   final repository = new PersistentHandlesRepositoryMock();
   final instances = new InstanceRepositoryMock();
   test('instantiation', () {
-    final e = new PersistentHandlesPageElement(vm, isolate, events, notifs,
-                                               repository, instances);
+    final e = new PersistentHandlesPageElement(
+        vm, isolate, events, notifs, repository, instances);
     expect(e, isNotNull, reason: 'element correctly created');
     expect(e.isolate, equals(isolate));
   });
   test('elements created after attachment', () async {
     final repository = new PersistentHandlesRepositoryMock(
-      getter: expectAsync((i) async {
-        expect(i, equals(isolate));
-        return const PersistentHandlesMock();
-      }, count: 1)
-    );
+        getter: expectAsync((i) async {
+      expect(i, equals(isolate));
+      return const PersistentHandlesMock();
+    }, count: 1));
     final instances = new InstanceRepositoryMock();
-    final e = new PersistentHandlesPageElement(vm, isolate, events, notifs,
-                                               repository, instances);
+    final e = new PersistentHandlesPageElement(
+        vm, isolate, events, notifs, repository, instances);
     document.body.append(e);
     await e.onRendered.first;
     expect(e.children.length, isNonZero, reason: 'has elements');