Create desktopCaptureThread with an Android message pump

This CL modifies DesktopCaptureDevice to create desktopCaptureThread
with an Android message pump, on Android. This allows the ScreenCapture
class and DesktopCapturerAndroid to run using only one thread, which
simplifies the locking requirements a lot.

Currently, a background thread is used because the Android APIs require
a looper backed thread to be passed to them. With this CL, we can
construct a Handler and Looper on the desktopCaptureThread.

We leave the release callback in because we want to use shared memory in
the future, which will require delayed release.

Bug: 352187279
Test: CQ
Change-Id: Ia0ba8e948e395f44c6b19a309ffaa9ab1470c05c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6677672
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Commit-Queue: Eliot Courtney <edcourtney@chromium.org>
Reviewed-by: Jordan Bayles <jophba@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1482048}