OnionSoup: Move synchronous_compositor_proxy|registry to //content/renderer/input

As an intermediate step to remove //content/renderer/android, we need to
move synchronous_compositor_proxy.cc/h and synchronous_compositor_registry.h
from //content/renderer/android to //content/renderer/input.

This CL moves the files and keeps building the files only for Android.

Bug: 960709
Change-Id: Ifefd22f7d28a893db8e9456bc2e087a1af14aa36
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1657085
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
Cr-Commit-Position: refs/heads/master@{#668751}
6 files changed