Reland "window-service: makes objects using Env take Env (or get from WindowService)"

This reverts commit 93a3a4b3d32211b674e56b0968f850905fb9238d.

Reason for revert: msan issue was fixed and landed (and wasn't triggered by this patch). Reverting the revert to reland.

Original change's description:
> Revert "window-service: makes objects using Env take Env (or get from WindowService)"
> 
> This reverts commit 04308f3df2ca0d062114eb938691e59137660775.
> 
> Reason for revert: Patch earlier in the chain caused failures on msan bot.
> 
> Original change's description:
> > window-service: makes objects using Env take Env (or get from WindowService)
> > 
> > This allows for multiple Envs at the same time.
> > 
> > BUG=847992
> > TEST=covered by tests
> > 
> > Change-Id: I20dda0f7e3fde50027c9c867562718e49152d238
> > Reviewed-on: https://chromium-review.googlesource.com/1167654
> > Reviewed-by: Michael Wasserman <msw@chromium.org>
> > Commit-Queue: Scott Violet <sky@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#581701}
> 
> TBR=sky@chromium.org,msw@chromium.org
> 
> Change-Id: If149ac9dc90f0ef6cec5e59f744cd0c3189d01e6
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 847992
> Reviewed-on: https://chromium-review.googlesource.com/1168402
> Reviewed-by: Scott Violet <sky@chromium.org>
> Commit-Queue: Scott Violet <sky@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#581715}

TBR=sky@chromium.org,msw@chromium.org

Change-Id: Id10e4d33b7cf619b4e14f1ed4c8f604cd2c96591
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 847992
Reviewed-on: https://chromium-review.googlesource.com/1168326
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581798}
10 files changed