Make access to color_space() agnostic of underlying type

Bug: webrtc:8651
Change-Id: Ic819f9264083b2ab99e7796b932f82e28af8c23b
Reviewed-on: https://chromium-review.googlesource.com/c/1344432Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Commit-Queue: Johannes Kron <kron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610013}

content/renderer/media/webrtc/media_stream_remote_video_source.cc

@@ -178,9 +178,9 @@ void MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::OnFrame(
         WebRtcToMediaVideoRotation(incoming_frame.rotation()));
   }
 
-  if (incoming_frame.color_space().has_value()) {
+  if (incoming_frame.color_space()) {
     video_frame->set_color_space(
-        WebRtcToMediaVideoColorSpace(incoming_frame.color_space().value())
+        WebRtcToMediaVideoColorSpace(*incoming_frame.color_space())
             .ToGfxColorSpace());
   }