You may want to wait until  issue 457438  is fixed since the codec-specifying mechanism is changing.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/779123fd5a7c241cfffa34e93c786b0ad96956b0

commit 779123fd5a7c241cfffa34e93c786b0ad96956b0
Author: servolk <servolk@chromium.org>
Date: Wed Jun 15 18:27:11 2016

Support HEVC through EME

Currently we support HEVC demuxing through regular MSE and ffmpeg code
paths. Now we need to add also support for HEVC playback (and
appropriate media mime type and codec support checks) through EME code
path as well.

BUG= 606564 

Review-Url: https://codereview.chromium.org/1909313002
Cr-Commit-Position: refs/heads/master@{#399964}

[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/chrome/browser/media/encrypted_media_supported_types_browsertest.cc
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/chromecast/chromecast.gyp
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/chromecast/renderer/DEPS
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/chromecast/renderer/key_systems_cast.cc
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/components/cdm/browser/DEPS
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/components/cdm/browser/cdm_message_filter_android.cc
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/media/base/eme_constants.h
[modify] https://crrev.com/779123fd5a7c241cfffa34e93c786b0ad96956b0/media/base/key_systems.cc