Fully delete third_party/android_sdk/androidx_browser

Bug: 1180183
Change-Id: Ia3fb3d6faa8bbe37142d3d38227c0bbd63368655
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2716123
Auto-Submit: Sam Maier <smaier@chromium.org>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#857165}
GitOrigin-RevId: a64d6ebb4b11989fc8e9ea71cf72099ab5ca131e