Extract the handling of the clean exit beacon from MetricsService. The extracted implementation sup…

components/metrics/metrics_pref_names.cc

 // Copyright 2014 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/metrics/metrics_pref_names.h"
 
 namespace metrics {
 namespace prefs {
 
 // Set once, to the current epoch time, on the first run of chrome on this
@@ skipping 65 matching lines @@
     "user_experience_metrics.stability.debugger_present";
 
 // Number of times the browser has not been run under a debugger.
 const char kStabilityDebuggerNotPresent[] =
     "user_experience_metrics.stability.debugger_not_present";
 
 // An enum value to indicate the execution phase the browser was in.
 const char kStabilityExecutionPhase[] =
     "user_experience_metrics.stability.execution_phase";
 
-// True if the previous run of the program exited cleanly.
-const char kStabilityExitedCleanly[] =
-    "user_experience_metrics.stability.exited_cleanly";
-
 // Number of times the session end did not complete.
 const char kStabilityIncompleteSessionEndCount[] =
     "user_experience_metrics.stability.incomplete_session_end_count";
 
 // Time when the app was last known to be running, in seconds since
 // the epoch.
 const char kStabilityLastTimestampSec[] =
     "user_experience_metrics.stability.last_timestamp_sec";
 
 // Number of times the application was launched since last report.
@@ skipping 28 matching lines @@
     "user_experience_metrics.stability.stats_version";
 
 // The keys below are strictly increasing counters over the lifetime of
 // a chrome installation. They are (optionally) sent up to the uninstall
 // survey in the event of uninstallation.
 const char kUninstallLaunchCount[] = "uninstall_metrics.launch_count";
 const char kUninstallMetricsUptimeSec[] = "uninstall_metrics.uptime_sec";
 
 }  // namespace prefs
 }  // namespace metrics