Add an automatic settings reset banner.

chrome/browser/prefs/chrome_pref_service_factory.cc

Index: chrome/browser/prefs/chrome_pref_service_factory.cc
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.cc b/chrome/browser/prefs/chrome_pref_service_factory.cc
index 170975e65c99b502231e1a38b07d450bb0a94377..be275e2316c219a15d5294c8bdb284a3b18e9fc3 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.cc
+++ b/chrome/browser/prefs/chrome_pref_service_factory.cc
@@ -16,6 +16,7 @@
 #include "base/prefs/pref_filter.h"
 #include "base/prefs/pref_notifier_impl.h"
 #include "base/prefs/pref_registry.h"
+#include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/pref_store.h"
 #include "base/prefs/pref_value_store.h"
@@ -24,6 +25,7 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/prefs/command_line_pref_store.h"
 #include "chrome/browser/prefs/pref_hash_filter.h"
+#include "chrome/browser/prefs/pref_hash_store.h"
 #include "chrome/browser/prefs/pref_hash_store_impl.h"
 #include "chrome/browser/prefs/pref_model_associator.h"
 #include "chrome/browser/prefs/pref_service_syncable.h"
@@ -242,13 +244,20 @@ scoped_ptr<PrefHashStoreImpl> GetPrefHashStoreImpl(
 #endif
 }
 
+void HandleResetEvent() {
+  g_browser_process->local_state()->SetInt64(
+      prefs::kProfilePreferenceResetTime,
+      base::Time::Now().ToInternalValue());
+}
+
 scoped_ptr<PrefHashFilter> CreatePrefHashFilter(
     scoped_ptr<PrefHashStore> pref_hash_store) {
   return make_scoped_ptr(new PrefHashFilter(pref_hash_store.Pass(),
                                             kTrackedPrefs,
                                             arraysize(kTrackedPrefs),
                                             kTrackedPrefsReportingIDsCount,
-                                            GetSettingsEnforcementLevel()));
+                                            GetSettingsEnforcementLevel(),
+                                            base::Bind(&HandleResetEvent)));
 }
 
 void PrepareBuilder(
@@ -412,4 +421,12 @@ void ResetPrefHashStore(const base::FilePath& profile_path) {
   GetPrefHashStoreImpl(profile_path)->Reset();
 }
 
+void RegisterPrefs(PrefRegistrySimple* registry) {
+  // Register the pref that maintains state about the last time a PrefHashFilter
+  // reset event occurred. Used to decide whether to show UI.

[gab, 2014/02/07 22:00:19]

I don't think a comment about what the pref does is necessary; all details
should be on the pref declaration's comment IMO.

[robertshield, 2014/02/10 02:30:53]

Done.

+  registry->RegisterInt64Pref(prefs::kProfilePreferenceResetTime, 0L);
+
+  PrefHashStoreImpl::RegisterPrefs(registry);
+}
+
 }  // namespace chrome_prefs