Updating android_aar_prebuilt rule to prevent unneeded args if the res folder is empty.

Updating android_aar_prebuilt rule to prevent unneeded args if the res folder is empty.

If archive res folder exists but is empty, android_aar_prebuilt should not
ad the 'generated_resource_dirs' and 'generated_resource_files' args.
This is an issue if an aar has both a R.txt file and and empty res
folder. In that case the generated __res.build_config file will
have a 'resources_dirs' arg for a folder that does not exist.

BUG=702606
R=agrieve@chromium.org
TEST=See crbug.com/702606 for steps to repro

[agrieve, 2017-03-17 14:41:36]

On 2017/03/17 14:37:49, mmcmahon wrote:

lgtm, but commit first line is a bit wonky: "rule to args if args if the res
folder is empty."

[mmcmahon, 2017-03-17 14:49:41]

Description was changed from

==========
Updating android_aar_prebuilt rule to args if args if the res folder is empty.

If archive res folder exists but is empty, android_aar_prebuilt should not
ad the 'generated_resource_dirs' and 'generated_resource_files' args.
This is an issue if an aar has both a R.txt file and and empty res
folder. In that case the generated __res.build_config file will
have a 'resources_dirs' arg for a folder that does not exist.

BUG=702606
R=agrieve@chromium.org
TEST=See crbug.com/702606 for steps to repro
==========

to

==========
Updating android_aar_prebuilt rule to args if args if the res folder is empty.

If archive res folder exists but is empty, android_aar_prebuilt should not
ad the 'generated_resource_dirs' and 'generated_resource_files' args.
This is an issue if an aar has both a R.txt file and and empty res
folder. In that case the generated __res.build_config file will
have a 'resources_dirs' arg for a folder that does not exist.

BUG=702606
R=agrieve@chromium.org
TEST=See crbug.com/702606 for steps to repro
==========

[mmcmahon, 2017-03-17 14:50:17]

Description was changed from

==========
Updating android_aar_prebuilt rule to args if args if the res folder is empty.

If archive res folder exists but is empty, android_aar_prebuilt should not
ad the 'generated_resource_dirs' and 'generated_resource_files' args.
This is an issue if an aar has both a R.txt file and and empty res
folder. In that case the generated __res.build_config file will
have a 'resources_dirs' arg for a folder that does not exist.

BUG=702606
R=agrieve@chromium.org
TEST=See crbug.com/702606 for steps to repro
==========

to

==========
Updating android_aar_prebuilt rule to prevent unneeded args if the res folder is
empty.

If archive res folder exists but is empty, android_aar_prebuilt should not
ad the 'generated_resource_dirs' and 'generated_resource_files' args.
This is an issue if an aar has both a R.txt file and and empty res
folder. In that case the generated __res.build_config file will
have a 'resources_dirs' arg for a folder that does not exist.

BUG=702606
R=agrieve@chromium.org
TEST=See crbug.com/702606 for steps to repro
==========

[mmcmahon, 2017-03-17 14:50:51]

Fixed up the commit description