Implement PasswordStoreProxyMac and SimplePasswordStoreMac.

components/password_manager/core/browser/password_store.h

Index: components/password_manager/core/browser/password_store.h
diff --git a/components/password_manager/core/browser/password_store.h b/components/password_manager/core/browser/password_store.h
index 91ec3b5bd197b031cd2972e60b4f350812335d2c..d875a51baeb605e74390dc432f67867f03ffaff9 100644
--- a/components/password_manager/core/browser/password_store.h
+++ b/components/password_manager/core/browser/password_store.h
@@ -26,6 +26,8 @@ namespace syncer {
 class SyncableService;
 }
 
+class PasswordStoreProxyMac;
+
 namespace password_manager {
 
 class AffiliatedMatchHelper;
@@ -290,6 +292,8 @@ class PasswordStore : protected PasswordStoreSync,
   FRIEND_TEST_ALL_PREFIXES(PasswordStoreTest, GetLoginImpl);
   FRIEND_TEST_ALL_PREFIXES(PasswordStoreTest,
                            UpdatePasswordsStoredForAffiliatedWebsites);
+  // TODO(vasilii): remove this together with PasswordStoreProxyMac.
+  friend class ::PasswordStoreProxyMac;

[vabr (Chromium), 2015/06/19 20:19:09]

One thing I did not understand -- why do you need to forward the protected calls
in the proxy? Is it because of tests? In production, nobody should call
protected methods on the proxy, and the proxy does not call them itself (all is
done in the backend). Would it work if you remove the friend declaration and
just forward the public methods in the proxy?

[vasilii, 2015/06/22 13:34:17]

Actually forwarding the protected calls is most important. There are things like
PasswordStore::observers_, PasswordStore::syncable_service_ etc. They should
live in PasswordStoreProxyMac then switching the backend is easier. In addition
the logic like notifying the observers just works. PasswordStoreMac becomes an
implementation detail of PasswordStoreProxyMac. Its public methods inherited
from PasswordStore are not needed anymore.

 
   // Schedule the given |func| to be run in the PasswordStore's own thread with
   // responses delivered to |consumer| on the current thread.