Reland "Don't use RSAPrivateKey in NSS integration code."

chrome/browser/chromeos/ownership/owner_settings_service_chromeos.h

Index: chrome/browser/chromeos/ownership/owner_settings_service_chromeos.h
diff --git a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.h b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.h
index 354450bada1cb453a8a64a45e77546fbbdcf9816..aea7cc03a24d3c05d5255668372acf487a7aa102 100644
--- a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.h
+++ b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.h
@@ -135,7 +135,9 @@ class OwnerSettingsServiceChromeOS : public ownership::OwnerSettingsService,
 
   // OwnerSettingsService protected interface overrides:
 
-  // Reloads private key from profile's NSS slots, responds via |callback|.
+  // Reloads private key from profile's NSS slots, responds via |callback|. On
+  // success, |private_key| is non-null, but if the private key doesn't exist,
+  // |private_key->key()| may be null.

[davidben, 2015/05/06 18:48:39]

This is really weird and, tbh, I don't think it makes much sense. But
OwnerSettingsService::IsOwnerAsync actually assumes this with the private_key_
check. I'm somewhat puzzled by that code but have left it alone for now. It
seems a boolean keypair_loaded_ would make much more sense, but I didn't want to
make this CL grow in scope that much.

Plus there's failure paths where ReloadKeypairImpl gives back a null
scoped_refptr<PrivateKey> so that gets more confusing...

dpolukhin: I imagine this should get a TODO of some sort. What would you like me
to write in there.

[Dmitry Polukhin, 2015/05/07 10:59:16]

NULL private key means that active user is not an owner. But public key should
be available. I'm not an original author of the code.

[davidben, 2015/05/07 20:51:44]

Right. But the question is whether this is signaled by |private_key| being null
or |private_key->key()| being null. Right now it's the latter. I think it's
overly confusing that you can have an existent PrivateKey with non-existent
RSAPrivateKey.

   void ReloadKeypairImpl(const base::Callback<
       void(const scoped_refptr<ownership::PublicKey>& public_key,
            const scoped_refptr<ownership::PrivateKey>& private_key)>& callback)