Add an automatic settings reset banner.

chrome/browser/prefs/tracked/tracked_atomic_preference.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 "chrome/browser/prefs/tracked/tracked_atomic_preference.h"
 
 #include "base/values.h"
 #include "chrome/browser/prefs/pref_hash_store_transaction.h"
 
 TrackedAtomicPreference::TrackedAtomicPreference(
     const std::string& pref_path,
     size_t reporting_id,
     size_t reporting_ids_count,
     PrefHashFilter::EnforcementLevel enforcement_level)
     : pref_path_(pref_path),
       helper_(pref_path, reporting_id, reporting_ids_count, enforcement_level) {
 }
 
 void TrackedAtomicPreference::OnNewValue(
     const base::Value* value,
     PrefHashStoreTransaction* transaction) const {
   transaction->StoreHash(pref_path_, value);
 }
 
-void TrackedAtomicPreference::EnforceAndReport(
+bool TrackedAtomicPreference::EnforceAndReport(
     base::DictionaryValue* pref_store_contents,
     PrefHashStoreTransaction* transaction) const {
   const base::Value* value = NULL;
   pref_store_contents->Get(pref_path_, &value);
   PrefHashStoreTransaction::ValueState value_state =
       transaction->CheckValue(pref_path_, value);
 
   helper_.ReportValidationResult(value_state);
 
   TrackedPreferenceHelper::ResetAction reset_action =
       helper_.GetAction(value_state);
   helper_.ReportAction(reset_action);
 
-  if (reset_action == TrackedPreferenceHelper::DO_RESET)
+  bool was_reset = false;
+  if (reset_action == TrackedPreferenceHelper::DO_RESET) {
     pref_store_contents->RemovePath(pref_path_, NULL);
+    was_reset = true;
+  }
 
   if (value_state != PrefHashStoreTransaction::UNCHANGED) {
     // Store the hash for the new value (whether it was reset or not).
     const base::Value* new_value = NULL;
     pref_store_contents->Get(pref_path_, &new_value);
     transaction->StoreHash(pref_path_, new_value);
   }
+
+  return was_reset;
 }