Add an automatic settings reset banner.

chrome/browser/prefs/pref_hash_store_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/prefs/pref_hash_store_impl.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/time/time.h"
 #include "base/values.h"
 #include "chrome/common/pref_names.h"
 
 PrefHashStoreImpl::PrefHashStoreImpl(const std::string& hash_store_id,
                                      const std::string& seed,
                                      const std::string& device_id,
                                      PrefService* local_state)
     : hash_store_id_(hash_store_id),
       pref_hash_calculator_(seed, device_id),
       local_state_(local_state),
       initial_hashes_dictionary_trusted_(IsHashDictionaryTrusted()) {
   UMA_HISTOGRAM_BOOLEAN("Settings.HashesDictionaryTrusted",
                         initial_hashes_dictionary_trusted_);
 }
 
 // static
 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() {
   DictionaryPrefUpdate update(local_state_, prefs::kProfilePreferenceHashes);
 
   // Remove the dictionary corresponding to the profile name, which may have a
   // '.'
   update->RemoveWithoutPathExpansion(hash_store_id_, NULL);
 }
 
@@ skipping 113 matching lines @@
     for (base::DictionaryValue::Iterator it(*split_value); !it.IsAtEnd();
          it.Advance()) {
       // Keep the common part from the old |keyed_path| and replace the key to
       // get the new |keyed_path|.
       keyed_path.replace(common_part_length, std::string::npos, it.key());
       StoreHashInternal(keyed_path, &it.value(), &update);
     }
   }
 }
 
+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;
   if (update->Get()->GetDictionaryWithoutPathExpansion(hash_store_id_,
                                                        &hashes_dict)) {
     hashes_dict->Remove(path, NULL);
   }
   UpdateHashOfHashes(hashes_dict, update);
 }
 
@@ skipping 56 matching lines @@
       !pref_hash_dicts->GetDictionaryWithoutPathExpansion(
           internals::kHashOfHashesPref, &hash_of_hashes_dict) ||
       !hash_of_hashes_dict->GetStringWithoutPathExpansion(
           hash_store_id_, &hash_of_hashes)) {
     return false;
   }
 
   return pref_hash_calculator_.Validate(
       hash_store_id_, hashes_dict, hash_of_hashes) == PrefHashCalculator::VALID;
 }