Move preference MACs to the protected preference stores.

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 bd35e293046fb3f7a9d1183eed5490b7339873dc..8fb28447b0736a9a48ec2c5c6a6cbed07d7a648c 100644
--- a/chrome/browser/prefs/pref_hash_filter.cc
+++ b/chrome/browser/prefs/pref_hash_filter.cc
@@ -96,15 +96,15 @@ void PrefHashFilter::ClearResetTime(PrefService* user_prefs) {
   user_prefs->ClearPref(prefs::kPreferenceResetTime);
 }
 
-void PrefHashFilter::Initialize(const PrefStore& pref_store) {
+void PrefHashFilter::Initialize(base::DictionaryValue* pref_store_contents) {
   scoped_ptr<PrefHashStoreTransaction> hash_store_transaction(
-      pref_hash_store_->BeginTransaction());
+      pref_hash_store_->BeginTransaction(pref_store_contents));
   for (TrackedPreferencesMap::const_iterator it = tracked_paths_.begin();
        it != tracked_paths_.end(); ++it) {
     const std::string& initialized_path = it->first;
     const TrackedPreference* initialized_preference = it->second;
     const base::Value* value = NULL;
-    pref_store.GetValue(initialized_path, &value);
+    pref_store_contents->Get(initialized_path, &value);
     initialized_preference->OnNewValue(value, hash_store_transaction.get());
   }
 }
@@ -119,14 +119,14 @@ void PrefHashFilter::FilterUpdate(const std::string& path) {
 
 // Updates the stored hashes for |changed_paths_| before serializing data to
 // disk. This is required as storing the hash everytime a pref's value changes
-// is too expensive (see perf regression @ http://crbug.com/331273).
+// is too expensive (see perf roegression @ http://crbug.com/331273).
 void PrefHashFilter::FilterSerializeData(
-    const base::DictionaryValue* pref_store_contents) {
+    base::DictionaryValue* pref_store_contents) {
   if (!changed_paths_.empty()) {
     base::TimeTicks checkpoint = base::TimeTicks::Now();
     {
       scoped_ptr<PrefHashStoreTransaction> hash_store_transaction(
-          pref_hash_store_->BeginTransaction());
+          pref_hash_store_->BeginTransaction(pref_store_contents));
       for (ChangedPathsMap::const_iterator it = changed_paths_.begin();
            it != changed_paths_.end(); ++it) {
         const std::string& changed_path = it->first;
@@ -143,21 +143,6 @@ void PrefHashFilter::FilterSerializeData(
     UMA_HISTOGRAM_TIMES("Settings.FilterSerializeDataTime",
                         base::TimeTicks::Now() - checkpoint);
   }
-
-  // Flush the |pref_hash_store_| to disk if it has pending writes. This is done
-  // here in an effort to flush the hash store to disk as close as possible to
-  // its matching value store (currently being flushed) to reduce the likelihood
-  // of MAC corruption in race condition scenarios where a crash occurs in the
-  // 10 seconds window where it would typically be possible that only one
-  // of the two stores has been flushed to disk (this now explicitly makes this
-  // race window as small as possible).
-  // Note that, if the |pref_hash_store_| has pending writes, this call will
-  // force serialization of its store to disk. As FilterSerializeData is already
-  // intercepting the serialization of its value store this would result in an
-  // infinite loop should the hash store also be the value store -- thus this
-  // should be removed when we move to such a model (where it will no longer be
-  // necessary anyways).
-  pref_hash_store_->CommitPendingWrite();
 }
 
 void PrefHashFilter::FinalizeFilterOnLoad(
@@ -170,7 +155,7 @@ void PrefHashFilter::FinalizeFilterOnLoad(
   bool did_reset = false;
   {
     scoped_ptr<PrefHashStoreTransaction> hash_store_transaction(
-        pref_hash_store_->BeginTransaction());
+        pref_hash_store_->BeginTransaction(pref_store_contents));
     for (TrackedPreferencesMap::const_iterator it = tracked_paths_.begin();
          it != tracked_paths_.end(); ++it) {
       if (it->second->EnforceAndReport(pref_store_contents,