Integrate registry_hash_store_contents with the rest of tracked prefs.

components/user_prefs/tracked/pref_hash_store.h

Index: components/user_prefs/tracked/pref_hash_store.h
diff --git a/components/user_prefs/tracked/pref_hash_store.h b/components/user_prefs/tracked/pref_hash_store.h
index 2fdc617301ae1fea64526ae16fe5d6621c272406..a1a12f23fc51762014f53e472dd4ea4803637df2 100644
--- a/components/user_prefs/tracked/pref_hash_store.h
+++ b/components/user_prefs/tracked/pref_hash_store.h
@@ -10,6 +10,11 @@
 class HashStoreContents;
 class PrefHashStoreTransaction;
 
+namespace base {
+class DictionaryValue;
+class Value;
+}  // namespace base
+
 // Holds the configuration and implementation used to calculate and verify
 // preference MACs.
 // TODO(gab): Rename this class as it is no longer a store.
@@ -23,6 +28,13 @@ class PrefHashStore {
   // related transactions should correspond to the same underlying data store.
   virtual std::unique_ptr<PrefHashStoreTransaction> BeginTransaction(
       std::unique_ptr<HashStoreContents> storage) = 0;
+
+  virtual std::string ComputeMac(const std::string& path,

[gab, 2016/08/03 18:19:35]

Document these new methods. Something like

// Computes the MAC to be associated with |path| and |value| in this store.
PrefHashStoreTransaction typically uses this internally but it's also exposed
for users that want to compute MACs ahead of time for asynchronous operations.

[proberge, 2016/08/04 00:13:46]

Done.

+                                 const base::Value* new_value) = 0;

[gab, 2016/08/03 18:19:35]

s/new_value/value/ (this API doesn't care that it's "new")

[proberge, 2016/08/04 00:13:46]

Done.

+
+  virtual std::unique_ptr<base::DictionaryValue> ComputeSplitMacs(
+      const std::string& path,
+      const base::DictionaryValue* split_values) = 0;
 };
 
 #endif  // COMPONENTS_PREFS_TRACKED_PREF_HASH_STORE_H_