Revert of Add MemoryCoordinator (patchset #13 id:240001 of https://codereview.chromium.org/2094583002/ )

Reason for revert:
Broke mac build

Original issue's description:
> Add MemoryCoordinator
>
> This CL adds MemoryCoordinator mojo interface and
> its implementation. When --enable-features=MemoryCoordinator
> is specified the browser and renderers create their
> MemoryCoordinators. MemoryCoordinatorImpl (which lives in
> the browser process) creates a mojo message pipe when a
> renderer is launched.
>
> This CL doesn't add actual handling of memory events, which
> will be implemented in follow-up CLs.
>
> BUG=617492
>
> Committed: https://crrev.com/066dcbbad57a70ba5380a4a8cdd0572d89bdc279
> Cr-Commit-Position: refs/heads/master@{#405402}

TBR=chrisha@chromium.org,haraken@chromium.org,dcheng@chromium.org,jam@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=617492

Review-Url: https://codereview.chromium.org/2143353004
Cr-Commit-Position: refs/heads/master@{#405406}
28 files changed