[CrOS Tether] Add a static TruncateDeviceIdForLogs() function.

components/cryptauth/remote_device.h

 // Copyright 2014 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 COMPONENTS_CRYPTAUTH_REMOTE_DEVICE_H
 #define COMPONENTS_CRYPTAUTH_REMOTE_DEVICE_H
 
 #include <string>
 #include <vector>
 
@@ skipping 24 matching lines @@
 
   // Returns a unique ID for the device.
   std::string GetDeviceId() const;
 
   // Returns a shortened device ID for the purpose of concise logging (device
   // IDs are often so long that logs are difficult to read). Note that this
   // ID is not guaranteed to be unique, so it should only be used for log.
   std::string GetTruncatedDeviceIdForLogs() const;
 
   bool operator==(const RemoteDevice& other) const;
+
+  // Static method for truncated device ID for logs.
+  static std::string TruncateDeviceIdForLogs(const std::string& full_id);
 };
 
 typedef std::vector<RemoteDevice> RemoteDeviceList;
 
 }  // namespace cryptauth
 
 #endif  // COMPONENTS_CRYPTAUTH_REMOTE_DEVICE_H