My understanding is that some aspects of cast support will also require DisplayCompositor changes.

I have half a patch that does the naive thing and cleaves a mojo interface at the current ash::CastConfigDelegate boundary.

I did some high level poking at the media router code, and I wonder if all of that could go into its own service.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4ff45be6d3af36828f1042a839cbb5a6a60f6563

commit 4ff45be6d3af36828f1042a839cbb5a6a60f6563
Author: erg <erg@chromium.org>
Date: Sat Dec 03 00:47:22 2016

mash: Change CastConfigDelegate to a mojoified CastConfigClient.

BUG= 665074 

Review-Url: https://codereview.chromium.org/2525563003
Cr-Commit-Position: refs/heads/master@{#436107}

[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/BUILD.gn
[add] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/cast_config_controller.cc
[add] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/cast_config_controller.h
[delete] https://crrev.com/119a280cbd120b06bd7ce82f890624de5ca57e13/ash/common/cast_config_delegate.cc
[delete] https://crrev.com/119a280cbd120b06bd7ce82f890624de5ca57e13/ash/common/cast_config_delegate.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/mojo_interface_factory.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/system/chromeos/cast/tray_cast.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/system/chromeos/cast/tray_cast.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/system/tray/system_tray_delegate.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/system/tray/system_tray_delegate.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/wm_shell.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/common/wm_shell.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/mus/manifest.json
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/public/interfaces/BUILD.gn
[add] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/public/interfaces/cast_config.mojom
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/test/tray_cast_test_api.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/ash/test/tray_cast_test_api.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/apps/app_browsertest_util.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/apps/app_browsertest_util.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/chrome_content_browser_manifest_overlay.json
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/chromeos/file_manager/external_filesystem_apitest.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/BUILD.gn
[rename] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/ash/cast_config_client_media_router.cc
[add] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/ash/cast_config_client_media_router.h
[delete] https://crrev.com/119a280cbd120b06bd7ce82f890624de5ca57e13/chrome/browser/ui/ash/cast_config_delegate_media_router.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/ash/system_tray_tray_cast_browsertest_media_router_chromeos.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.cc
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
[modify] https://crrev.com/4ff45be6d3af36828f1042a839cbb5a6a60f6563/chrome/test/BUILD.gn