[Chromoting] Move SharedSecretHash from Me2MeHostAuthenticatorFactory to AuthenticationMethod.

remoting/protocol/authentication_method.cc

 // Copyright (c) 2012 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.
 
 #include "remoting/protocol/authentication_method.h"
 
+#include "base/base64.h"
 #include "base/logging.h"
 #include "crypto/hmac.h"
 #include "remoting/protocol/auth_util.h"
 #include "remoting/protocol/v1_authenticator.h"
 #include "remoting/protocol/v2_authenticator.h"
 
 namespace remoting {
 namespace protocol {
 
 // static
@@ skipping 78 matching lines @@
 
 bool AuthenticationMethod::operator ==(
     const AuthenticationMethod& other) const {
   if (!is_valid())
     return !other.is_valid();
   if (!other.is_valid())
     return false;
   return hash_function_ == other.hash_function_;
 }
 
+bool SharedSecretHash::Parse(const std::string& as_string) {
+  size_t separator = as_string.find(':');
+  if (separator == std::string::npos)
+    return false;
+
+  std::string function_name = as_string.substr(0, separator);
+  if (function_name == "plain") {
+    hash_function = AuthenticationMethod::NONE;
+  } else if (function_name == "hmac") {
+    hash_function = AuthenticationMethod::HMAC_SHA256;
+  } else {
+    return false;
+  }
+
+  if (!base::Base64Decode(as_string.substr(separator + 1), &value)) {
+    return false;
+  }
+
+  return true;
+}
+
 }  // namespace protocol
 }  // namespace remoting