Revert of Remove remote tree host and some related input and metro_driver code (patchset #5 id:80001 of https://codereview.chromium.org/1586843002/ )

Reason for revert:
Suspecting that this is breaking the Webkit Win (dbg) builder.

First failed build:
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win%20Builder%20%28dbg%29/builds/88362

Original issue's description:
> Remove remote tree host and some related input and metro_driver code
>
> Part of continued stripping out of Metro/Win8/Immersive mode.
>
> BUG=558054
>
> Committed: https://crrev.com/5cc04f70e424020d8afe49bdc4c1c76683f0ea7b
> Cr-Commit-Position: refs/heads/master@{#370068}

TBR=sky@chromium.org,thestig@chromium.org,shuchen@chromium.org,ananta@chromium.org,dpranke@chromium.org,scottmg@chromium.org
NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
BUG=558054

Review URL: https://codereview.chromium.org/1602403002

Cr-Commit-Position: refs/heads/master@{#370290}
63 files changed