devicelab: add more hot-reload metrics (#7602)

dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart

diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart
index a9d7320..9eeb3bd 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart
@@ -26,7 +26,10 @@
     return new TaskResult.successFromFile(benchmarkFile,
         benchmarkScoreKeys: <String>[
           'hotReloadMillisecondsToFrame',
-          'hotRestartMillisecondsToFrame'
+          'hotRestartMillisecondsToFrame',
+          'hotReloadDevFSSyncMilliseconds',
+          'hotReloadFlutterReassembleMilliseconds',
+          'hotReloadVMReloadMilliseconds',
         ]);
   });
 }