Note: The CL implementing a temporary fix (and which will need to be reverted as part of this work) is https://chromium-review.googlesource.com/c/chromium/src/+/644446.

I don't think it's worth fixing this for the current client implementation; let's focus on the website.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ab84842cc2906adf2f2837c35736cd6f65d3c074

commit ab84842cc2906adf2f2837c35736cd6f65d3c074
Author: Erik Jensen <rkjnsn@chromium.org>
Date: Mon Oct 02 19:38:09 2017

Add discrete caps/num lock fields to event protocol

Previously, there was a single field for all lock states. This was
problematic, because some platforms only support caps lock. These
platforms were thus forced to include bogus state for num lock. Making
them separate fields allows these platforms to specify only the
caps-lock state.

Bug:  760731 
Change-Id: Id72bbb09e1a8ed218cf77496cfd76cf1df8c97c0
Reviewed-on: https://chromium-review.googlesource.com/692752
Commit-Queue: Erik Jensen <rkjnsn@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505725}
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/client/input/normalizing_input_filter_cros.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/client/input/normalizing_input_filter_mac.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/client/plugin/pepper_input_handler.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/host/input_injector_chromeos.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/host/input_injector_mac.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/host/input_injector_win.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/host/input_injector_x11.cc
[modify] https://crrev.com/ab84842cc2906adf2f2837c35736cd6f65d3c074/remoting/proto/event.proto