I don't think Chromium has dropped support for kernels <= 3.16. ChromiumOS uses 3.4, 3.8, 3.10, and 3.14 depending on device. All of those are less than 3.16, but as far as I know, ChromiumOS is not going away.
It appears a patch needs to be cherry-picked back; a pretty common task for people that maintain older kernels. It's very common to backport patches to drivers you care about (because new kernel versions always introduce bugs in your obscure hardware, you only backport stuff that doesn't already work). There is even a system for doing it in an automated manner: http://drvbp1.linux-foundation.org/~mcgrof/rel-html/backport...
It appears a patch needs to be cherry-picked back; a pretty common task for people that maintain older kernels. It's very common to backport patches to drivers you care about (because new kernel versions always introduce bugs in your obscure hardware, you only backport stuff that doesn't already work). There is even a system for doing it in an automated manner: http://drvbp1.linux-foundation.org/~mcgrof/rel-html/backport...