Use dartfmt on Observatory code

runtime/observatory/lib/src/models/repositories/metric.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file
 
 part of models;
 
-enum MetricBufferSize {
-  n10samples,
-  n100samples,
-  n1000samples
-}
+enum MetricBufferSize { n10samples, n100samples, n1000samples }
 
-enum MetricSamplingRate {
-  off,
-  e100ms,
-  e1s,
-  e2s,
-  e4s,
-  e8s
-}
+enum MetricSamplingRate { off, e100ms, e1s, e2s, e4s, e8s }
 
 abstract class MetricRepository {
   Future<Iterable<Metric>> list(IsolateRef isolate);
   void setSamplingRate(IsolateRef isolate, Metric metric, MetricSamplingRate r);
   MetricSamplingRate getSamplingRate(IsolateRef isolate, Metric metric);
   void setBufferSize(IsolateRef isolate, Metric metric, MetricBufferSize r);
   MetricBufferSize getBufferSize(IsolateRef isolate, Metric metric);
   Iterable<MetricSample> getSamples(IsolateRef isolate, Metric metric);
   double getMinValue(IsolateRef isolate, Metric metric);
   double getMaxValue(IsolateRef isolate, Metric metric);
 }