[CRD iOS] Implementing save to keychain and user defaults for login info. Refactor remoting service.

remoting/client/ios/keychain_wrapper.h

Index: remoting/client/ios/keychain_wrapper.h
diff --git a/remoting/client/ios/keychain_wrapper.h b/remoting/client/ios/keychain_wrapper.h
new file mode 100644
index 0000000000000000000000000000000000000000..d92b6ae91df6ec3149c77e5a061a59c6bda3ebfb
--- /dev/null
+++ b/remoting/client/ios/keychain_wrapper.h
@@ -0,0 +1,26 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef REMOTING_CLIENT_IOS_KEYCHAIN_WRAPPER_H_
+#define REMOTING_CLIENT_IOS_KEYCHAIN_WRAPPER_H_
+
+#import <Foundation/Foundation.h>
+
+@class UserInfo;
+
+// Class to abstract the details from how iOS wants to write to the keychain.
+// TODO(nicholss): This will have to be futher refactored when we integrate
+// with the private Google auth.
+@interface KeychainWrapper : NSObject
+
+// Save a refresh token to the keychain.
+- (void)setRefreshToken:(NSString*)refreshToken;
+// Get the refresh token from the keychain, if there is one.
+- (NSString*)refreshToken;
+// Reset the keychain and the cache.
+- (void)resetKeychainItem;
+
+@end
+
+#endif  //  REMOTING_CLIENT_IOS_KEYCHAIN_WRAPPER_H_