* add Android instrumentation test

* add devicelab test

* add to manifest.yaml

* rename _smoke_test.dart to _smoketest.dart to prevent flutter test from picking it up

* volatile fields; style fixes

* use ConditionVariable; fix sh script

This reverts commit 4bbf158b.

* Revert "Update reference to url_launcher plugin in Gallery pubspec (#9879)"

This reverts commit 96a04dea.

* Revert "Revert "Revert plugin use in gallery (#9838)" (#9877)"

This reverts commit ede72a80.

This reverts commit 4bbf158b.

* Revert "add Podfile (#9835)"

This reverts commit 74e65675.

* Revert "update ref to url_launcher plugin in Flutter Gallery (#9833)"

This reverts commit 30c49781.

* Revert "Use url_launcher plugin in Flutter Gallery (#9751)"

This reverts commit 02dfd6be.

Enable plugin infra for both iOS and Android post-#9791.

Brings hello_world and flutter_gallery Android code in line with the
corresponding iOS code.