DeviceScheduledUpdateChecker: Refactor reset state

This change moves a function that semantically belongs in ResetState.

BUG=924762
TEST=Unit tests.

Change-Id: I8a8d0c446cda8e8a828857d80031b97e28206fc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1757459
Commit-Queue: Abhishek Bhardwaj <abhishekbh@chromium.org>
Reviewed-by: Sergey Poromov <poromov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691019}

chrome/browser/chromeos/policy/scheduled_update_checker/device_scheduled_update_checker.cc

@@ -352,7 +352,6 @@ void DeviceScheduledUpdateChecker::OnScheduledUpdateCheckDataChanged() {
       cros_settings_->GetPref(chromeos::kDeviceScheduledUpdateCheck);
   if (!value) {
     ResetState();
-    os_and_policies_update_checker_.Stop();
     return;
   }
 
@@ -542,6 +541,7 @@ void DeviceScheduledUpdateChecker::OnUpdateCheckCompletion(
 void DeviceScheduledUpdateChecker::ResetState() {
   update_check_timer_.reset();
   scheduled_update_check_data_ = base::nullopt;
+  os_and_policies_update_checker_.Stop();
   start_update_check_timer_task_executor_.Stop();
 }