Move HostKeyPair into protocol::KeyPair.

remoting/host/remoting_me2me_host.cc

Index: remoting/host/remoting_me2me_host.cc
diff --git a/remoting/host/remoting_me2me_host.cc b/remoting/host/remoting_me2me_host.cc
index d676b8f93d1707624ea4e19c1002e5cbc6c76023..6ad94bd5c509c51546b7a1980d10b5688bcaf9d4 100644
--- a/remoting/host/remoting_me2me_host.cc
+++ b/remoting/host/remoting_me2me_host.cc
@@ -291,7 +291,7 @@ class HostProcess
 
   std::string host_id_;
   protocol::SharedSecretHash host_secret_hash_;
-  HostKeyPair key_pair_;
+  protocol::KeyPair key_pair_;
   std::string oauth_refresh_token_;
   std::string serialized_config_;
   std::string xmpp_login_;
@@ -523,7 +523,7 @@ void HostProcess::CreateAuthenticatorFactory() {
 
   scoped_ptr<protocol::AuthenticatorFactory> factory(
       new protocol::Me2MeHostAuthenticatorFactory(
-          local_certificate, *key_pair_.private_key(), host_secret_hash_));
+          local_certificate, key_pair_.Copy(), host_secret_hash_));
 #if defined(OS_POSIX)
   // On Linux and Mac, perform a PAM authorization step after authentication.
   factory.reset(new PamAuthorizationFactory(factory.Pass()));
@@ -685,7 +685,13 @@ bool HostProcess::ApplyConfig(scoped_ptr<JsonHostConfig> config) {
     return false;
   }
 
-  if (!key_pair_.Load(*config)) {
+  std::string key_base64;
+  if (!config->GetString(kPrivateKeyConfigPath, &key_base64)) {
+    LOG(ERROR) << "Private key wasn't found in the config file.";
+    return false;
+  }
+
+  if (!key_pair_.LoadFromString(key_base64)) {
     return false;
   }