[CrOS MultiDevice] Add cryptauth::RemoteDeviceRef::operator!=.

Bug: 824568
Change-Id: Ia0c761353aff3ca86848e36ec90f85d6a7ff7373
Reviewed-on: https://chromium-review.googlesource.com/1112953Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570091}

components/cryptauth/remote_device_ref.cc

@@ -60,6 +60,10 @@ bool RemoteDeviceRef::operator==(const RemoteDeviceRef& other) const {
   return *remote_device_ == *other.remote_device_;
 }
 
+bool RemoteDeviceRef::operator!=(const RemoteDeviceRef& other) const {
+  return !(*this == other);
+}
+
 bool RemoteDeviceRef::operator<(const RemoteDeviceRef& other) const {
   return *remote_device_ < *other.remote_device_;
 }

components/cryptauth/remote_device_ref.h

@@ -83,9 +83,7 @@ class RemoteDeviceRef {
   std::string GetTruncatedDeviceIdForLogs() const;
 
   bool operator==(const RemoteDeviceRef& other) const;
-
-  // This function is necessary in order to use |RemoteDeviceRef| as a key of a
-  // std::map.
+  bool operator!=(const RemoteDeviceRef& other) const;
   bool operator<(const RemoteDeviceRef& other) const;
 
  private: