Format all remaining unformatted runtime files other than multitests.

runtime/observatory/lib/src/elements/sample_buffer_control.dart

Index: runtime/observatory/lib/src/elements/sample_buffer_control.dart
diff --git a/runtime/observatory/lib/src/elements/sample_buffer_control.dart b/runtime/observatory/lib/src/elements/sample_buffer_control.dart
index c2984b9f334285736b814a66c79c300d7a99fd08..3661c7cfd82c28929a51f9f747e43c28f4239cf7 100644
--- a/runtime/observatory/lib/src/elements/sample_buffer_control.dart
+++ b/runtime/observatory/lib/src/elements/sample_buffer_control.dart
@@ -223,8 +223,8 @@ class SampleBufferControlElement extends HtmlElement implements Renderable {
         ..value = tagToString(_tag)
         ..children = values.map((tag) {
           return new OptionElement(
-              value: tagToString(tag),
-              selected: _tag == tag)..text = tagToString(tag);
+              value: tagToString(tag), selected: _tag == tag)
+            ..text = tagToString(tag);
         }).toList(growable: false)
         ..onChange.listen((_) {
           _tag = values[s.selectedIndex];