Creating a preference for storing a sync password hash.

chrome/browser/password_manager/simple_password_store_mac.h

Index: chrome/browser/password_manager/simple_password_store_mac.h
diff --git a/chrome/browser/password_manager/simple_password_store_mac.h b/chrome/browser/password_manager/simple_password_store_mac.h
index 4c95d561e77d427ad9df85b835133308037e0655..3acfaeb747114f6c9e3057d492bb395c4fbd8bea 100644
--- a/chrome/browser/password_manager/simple_password_store_mac.h
+++ b/chrome/browser/password_manager/simple_password_store_mac.h
@@ -8,6 +8,8 @@
 #include "base/macros.h"
 #include "components/password_manager/core/browser/password_store_default.h"
 
+class PrefService;
+
 // The same as PasswordStoreDefault but running on the dedicated thread. The
 // owner is responsible for the thread lifetime.
 class SimplePasswordStoreMac : public password_manager::PasswordStoreDefault {
@@ -32,7 +34,8 @@ class SimplePasswordStoreMac : public password_manager::PasswordStoreDefault {
   ~SimplePasswordStoreMac() override;
 
  private:
-  bool Init(const syncer::SyncableService::StartSyncFlare& flare) override;
+  bool Init(const syncer::SyncableService::StartSyncFlare& flare,
+            PrefService* prefs) override;
 
   DISALLOW_COPY_AND_ASSIGN(SimplePasswordStoreMac);
 };