Protect the kSyncRemainingRollbackTries pref.

BUG=387933

Review URL: https://codereview.chromium.org/347103005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@279230 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/prefs/chrome_pref_service_factory.cc

@@ -40,6 +40,7 @@
 #include "chrome/common/pref_names.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/search_engines/search_engines_pref_names.h"
+#include "components/sync_driver/pref_names.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/pref_names.h"
@@ -180,10 +181,15 @@ const PrefHashFilter::TrackedPreferenceMetadata kTrackedPrefs[] = {
     PrefHashFilter::ENFORCE_ON_LOAD,
     PrefHashFilter::TRACKING_STRATEGY_ATOMIC
   },
+  {
+    17, sync_driver::prefs::kSyncRemainingRollbackTries,
+    PrefHashFilter::ENFORCE_ON_LOAD,
+    PrefHashFilter::TRACKING_STRATEGY_ATOMIC
+  },
 };
 
 // The count of tracked preferences IDs across all platforms.
-const size_t kTrackedPrefsReportingIDsCount = 17;
+const size_t kTrackedPrefsReportingIDsCount = 18;
 COMPILE_ASSERT(kTrackedPrefsReportingIDsCount >= arraysize(kTrackedPrefs),
                need_to_increment_ids_count);