Move preference MACs to the protected preference stores.

chrome/browser/prefs/pref_hash_store.h

Index: chrome/browser/prefs/pref_hash_store.h
diff --git a/chrome/browser/prefs/pref_hash_store.h b/chrome/browser/prefs/pref_hash_store.h
index a6d97277b70b61acf57a3e3a9d64dd79bd2be7db..4370b141a5c40546cd5550cab7376ae947454b9b 100644
--- a/chrome/browser/prefs/pref_hash_store.h
+++ b/chrome/browser/prefs/pref_hash_store.h
@@ -9,6 +9,10 @@
 
 class PrefHashStoreTransaction;
 
+namespace base {
+class DictionaryValue;
+}  // namespace base
+
 // Stores hashes of and verifies preference values via
 // PrefHashStoreTransactions.
 class PrefHashStore {
@@ -17,11 +21,8 @@ class PrefHashStore {
 
   // Returns a PrefHashStoreTransaction which can be used to perform a series
   // of checks/transformations on the hash store.
-  virtual scoped_ptr<PrefHashStoreTransaction> BeginTransaction() = 0;
-
-  // Commits this store to disk if it has changed since the last call to this
-  // method.
-  virtual void CommitPendingWrite() = 0;
+  virtual scoped_ptr<PrefHashStoreTransaction> BeginTransaction(
+      base::DictionaryValue* storage) = 0;
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_HASH_STORE_H_