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..f67e9bff95e58266a10036af5819c5d1cb8151c7 100644
--- a/chrome/browser/prefs/pref_hash_filter.h
+++ b/chrome/browser/prefs/pref_hash_filter.h
@@ -10,6 +10,8 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/scoped_ptr.h"
@@ -17,6 +19,7 @@
 #include "chrome/browser/prefs/pref_hash_store.h"
 #include "chrome/browser/prefs/tracked/tracked_preference.h"
 
+class PrefRegistrySimple;
 class PrefStore;
 
 namespace base {
@@ -29,6 +32,8 @@ class Value;
 // are changed.
 class PrefHashFilter : public PrefFilter {
  public:
+  typedef base::Callback<void(void)> PrefResetCallback;
+
   // Enforcement levels are defined in order of intensity; the next level always
   // implies the previous one and more.
   enum EnforcementLevel {
@@ -65,15 +70,19 @@ class PrefHashFilter : public PrefFilter {
   // |reporting_ids_count| is the count of all possible IDs (possibly greater
   // than |tracked_preferences_size|). |enforcement_level| determines when this
   // filter will enforce factory defaults upon detecting an untrusted preference
-  // value.
+  // value. |reset_callback| is called when a reset event occurs.
   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 PrefResetCallback& reset_callback);
 
   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 +94,11 @@ 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();
+
  private:
   // A map of paths to TrackedPreferences; this map owns this individual
   // TrackedPreference objects.
@@ -107,6 +121,8 @@ class PrefHashFilter : public PrefFilter {
   // FilterSerializeData.
   ChangedPathsMap changed_paths_;
 
+  PrefResetCallback reset_callback_;
+
   DISALLOW_COPY_AND_ASSIGN(PrefHashFilter);
 };