[ESLint] Fix violations when enabling curly rule in eslint.

tracing/tracing/model/timed_event.html

Index: tracing/tracing/model/timed_event.html
diff --git a/tracing/tracing/model/timed_event.html b/tracing/tracing/model/timed_event.html
index aef562064a0a83a6f4f16eea617a90fbe470c156..c7ec3c0006f2c17787660684f42264414f857c25 100644
--- a/tracing/tracing/model/timed_event.html
+++ b/tracing/tracing/model/timed_event.html
@@ -46,8 +46,9 @@ tr.exportTo('tr.model', function() {
     // Returns true if 'that' TimedEvent is fully contained within 'this' timed
     // event.
     bounds: function(that, opt_precisionUnit) {
-      if (opt_precisionUnit === undefined)
+      if (opt_precisionUnit === undefined) {
         opt_precisionUnit = tr.b.TimeDisplayModes.ms;
+      }
 
       var startsBefore = opt_precisionUnit.roundedLess(that.start, this.start);
       var endsAfter = opt_precisionUnit.roundedLess(this.end, that.end);