Add an automatic settings reset banner.

chrome/browser/prefs/pref_hash_store_impl.cc

Index: chrome/browser/prefs/pref_hash_store_impl.cc
diff --git a/chrome/browser/prefs/pref_hash_store_impl.cc b/chrome/browser/prefs/pref_hash_store_impl.cc
index 205102cecc4a70c3fd6667aa700a73fd7f83f714..6b3e7647ad43a495d727dbd68c4ffb21d2fbe413 100644
--- a/chrome/browser/prefs/pref_hash_store_impl.cc
+++ b/chrome/browser/prefs/pref_hash_store_impl.cc
@@ -8,6 +8,7 @@
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
+#include "base/time/time.h"
 #include "base/values.h"
 #include "chrome/common/pref_names.h"
 
@@ -28,6 +29,9 @@ void PrefHashStoreImpl::RegisterPrefs(PrefRegistrySimple* registry) {
   // Register the top level dictionary to map profile names to dictionaries of
   // tracked preferences.
   registry->RegisterDictionaryPref(prefs::kProfilePreferenceHashes);
+  // Register the pref that maintains state about the last time a reset event
+  // occurred. Used to decide whether to show UI.
+  registry->RegisterInt64Pref(prefs::kProfilePreferenceResetTime, 0L);
 }
 
 void PrefHashStoreImpl::Reset() {
@@ -161,6 +165,11 @@ void PrefHashStoreImpl::StoreSplitHash(
   }
 }
 
+void PrefHashStoreImpl::RecordResetEvent() {

[gab, 2014/02/05 15:23:52]

I think this method belongs on TrackedPreferenceHelper like the UMA reporting
methods.

The PrefHashStore only knows about hashes, not resets.

[robertshield, 2014/02/06 18:56:50]

Erik convinced me it should go on PrefHashFilter. Moved there.

+  local_state_->SetInt64(prefs::kProfilePreferenceResetTime,
+                         base::Time::Now().ToInternalValue());
+}
+
 void PrefHashStoreImpl::ClearPath(const std::string& path,
                                   DictionaryPrefUpdate* update) {
   base::DictionaryValue* hashes_dict = NULL;