Revert of RenderHostImpl::AddRoute - Turn a DCHECK to CHECK() (patchset #3 id:40001...

Revert of RenderHostImpl::AddRoute - Turn a DCHECK to CHECK() (patchset #3 id:40001 of https://codereview.chromium.org/657613003/)

Reason for revert:
This broke the perf bots, details in crbug.com/423691

BUG=423691

Original issue's description:
> RenderHostImpl::AddRoute - Turn a DCHECK to CHECK()
>
> This is to narrow down the cause of a crash bug and
> likely to crash. Please revert and let me know
> if you see this in the wild.
>
> R=nasko@chromium.org, kareng@chromium.org
> BUG=381990, 415059
>
> Committed: https://crrev.com/40e8a27bfd3c51ca92136c796d50e3f3a0d86c04
> Cr-Commit-Position: refs/heads/master@{#299591}

TBR=kareng@chromium.org,nasko@chromium.org,morrita@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=381990, 415059

Review URL: https://codereview.chromium.org/659763002

Cr-Commit-Position: refs/heads/master@{#299669}