Flush stability file after initialization

components/browser_watcher/features.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/browser_watcher/features.h"
 
 namespace browser_watcher {
 
-// Additional stability instrumentation.
+// Enables recording persistent stability information, which can later be
+// collected in the event of an unclean shutdown.
 const base::Feature kStabilityDebuggingFeature{
     "StabilityDebugging", base::FEATURE_DISABLED_BY_DEFAULT};
+// Controls the flushing behavior of the persistent stability information.
+const base::Feature kStabilityDebuggingFlushFeature{
+    "StabilityDebuggingFlush", base::FEATURE_DISABLED_BY_DEFAULT};
 
 }  // namespace browser_watcher