Add an automatic settings reset banner.

chrome/browser/prefs/pref_hash_filter.cc

Index: chrome/browser/prefs/pref_hash_filter.cc
diff --git a/chrome/browser/prefs/pref_hash_filter.cc b/chrome/browser/prefs/pref_hash_filter.cc
index 1935708f9e22ca39964f2580d8dd402d1d39d9b9..e91ed2015ee527acc6d40d4272757f3558f8cd8f 100644
--- a/chrome/browser/prefs/pref_hash_filter.cc
+++ b/chrome/browser/prefs/pref_hash_filter.cc
@@ -4,20 +4,26 @@
 
 #include "chrome/browser/prefs/pref_hash_filter.h"
 
+#include "base/callback.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
 #include "base/prefs/pref_store.h"
 #include "base/time/time.h"
 #include "base/values.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/prefs/tracked/tracked_atomic_preference.h"
 #include "chrome/browser/prefs/tracked/tracked_split_preference.h"
+#include "chrome/common/pref_names.h"
 
 PrefHashFilter::PrefHashFilter(
     scoped_ptr<PrefHashStore> pref_hash_store,
     const TrackedPreferenceMetadata tracked_preferences[],
     size_t tracked_preferences_size,
     size_t reporting_ids_count,
-    EnforcementLevel enforcement_level) {
+    EnforcementLevel enforcement_level,
+    const base::Closure& reset_callback) : reset_callback_(reset_callback) {
   DCHECK(pref_hash_store);
   DCHECK_GE(reporting_ids_count, tracked_preferences_size);
 
@@ -63,6 +69,12 @@ PrefHashFilter::~PrefHashFilter() {
   DCHECK(changed_paths_.empty());
 }
 
+void PrefHashFilter::RegisterPrefs(PrefRegistrySimple* registry) {
+  // 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 PrefHashFilter::Initialize(PrefStore* pref_store) {
   UMA_HISTOGRAM_BOOLEAN(
       "Settings.TrackedPreferencesInitializedForUnloadedProfile", true);
@@ -82,10 +94,16 @@ void PrefHashFilter::Initialize(PrefStore* pref_store) {
 void PrefHashFilter::FilterOnLoad(base::DictionaryValue* pref_store_contents) {
   DCHECK(pref_store_contents);
   base::TimeTicks checkpoint = base::TimeTicks::Now();
+  bool did_reset = false;
   for (TrackedPreferencesMap::const_iterator it = tracked_paths_.begin();
        it != tracked_paths_.end(); ++it) {
-    it->second->EnforceAndReport(pref_store_contents);
+    if (it->second->EnforceAndReport(pref_store_contents))
+      did_reset = true;
   }
+
+  if (did_reset)
+    reset_callback_.Run();
+
   // TODO(gab): Remove this histogram by Feb 21 2014; after sufficient timing
   // data has been gathered from the wild to be confident this doesn't
   // significantly affect startup.