Add an automatic settings reset banner.

chrome/browser/prefs/pref_hash_filter.h

Index: chrome/browser/prefs/pref_hash_filter.h
diff --git a/chrome/browser/prefs/pref_hash_filter.h b/chrome/browser/prefs/pref_hash_filter.h
index 38caa89494c46290e20f30180868c4d00ead0e24..41feec2fb081f9627ae41521982ea91c1de885f6 100644
--- a/chrome/browser/prefs/pref_hash_filter.h
+++ b/chrome/browser/prefs/pref_hash_filter.h
@@ -17,6 +17,7 @@
 #include "chrome/browser/prefs/pref_hash_store.h"
 #include "chrome/browser/prefs/tracked/tracked_preference.h"
 
+class PrefRegistrySimple;
 class PrefStore;
 
 namespace base {
@@ -74,6 +75,9 @@ class PrefHashFilter : public PrefFilter {
 
   virtual ~PrefHashFilter();
 
+  // Registers required local state preferences.
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
   // Initializes the PrefHashStore with hashes of the tracked preferences
   // in |pref_store|.
   void Initialize(PrefStore* pref_store);
@@ -85,6 +89,11 @@ class PrefHashFilter : public PrefFilter {
   virtual void FilterSerializeData(
       const base::DictionaryValue* pref_store_contents) OVERRIDE;
 
+ protected:
+  // Called when it is determined that a reset event has occurred. Exposed as
+  // protected for testing.
+  virtual void WriteResetEvent();

[erikwright (departed), 2014/02/06 20:04:03]

Use a callback instead. Isolates the global state access to
chrome_pref_service_factory

[robertshield, 2014/02/07 04:36:19]

Ok. Was torn between that and preserving all pref hash logic here. Switched to
callback.

+
  private:
   // A map of paths to TrackedPreferences; this map owns this individual
   // TrackedPreference objects.