Add support for overriding keystore for signing.

Add support for overriding keystore for signing.

This CL adds support for overriding android_keystore_path,
android_keystore_name, android_keystore_password from other config
files.

It also adds documentation to these arguments and removes 'default'
from their name.

The chromium debug key is still used by default for all builds.

BUG=479253
Committed: https://crrev.com/fbc342116e60698aae09bf4175a30bf8ccc14704
Cr-Commit-Position: refs/heads/master@{#347521}

[nyquist, 2015-09-04 18:52:44]

The CQ bit was checked by nyquist@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-04 18:52:56]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1311043014/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1311043014/1

[nyquist, 2015-09-04 18:52:57]

nyquist@chromium.org changed reviewers:
+ agrieve@chromium.org

[nyquist, 2015-09-04 18:52:57]

agrieve: PTAL

[agrieve, 2015-09-04 19:31:58]

On 2015/09/04 18:52:57, nyquist (sheriffing) wrote:
> agrieve: PTAL

lgtm if one comment addressed.

[agrieve, 2015-09-04 19:34:40]

https://codereview.chromium.org/1311043014/diff/1/build/config/android/rules.gni
File build/config/android/rules.gni (right):

https://codereview.chromium.org/1311043014/diff/1/build/config/android/rules....
build/config/android/rules.gni:1182: _keystore_path =
default_android_keystore_path
I think you want this to be android_keystore_path (no default)

[commit-bot: I haz the power, 2015-09-04 19:48:14]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-04 19:48:15]

Dry run: This issue passed the CQ dry run.

[nyquist, 2015-09-04 20:06:10]

nyquist@chromium.org changed reviewers:
+ dpranke@chromium.org

[nyquist, 2015-09-04 20:06:10]

dpranke: PTAL

FYI, the downstream change is here:
https://chrome-internal-review.googlesource.com/#/c/229301/

https://codereview.chromium.org/1311043014/diff/1/build/config/android/rules.gni
File build/config/android/rules.gni (right):

https://codereview.chromium.org/1311043014/diff/1/build/config/android/rules....
build/config/android/rules.gni:1182: _keystore_path =
default_android_keystore_path
On 2015/09/04 19:34:40, agrieve wrote:
> I think you want this to be android_keystore_path (no default)

Doh! Yes!

[Dirk Pranke, 2015-09-04 22:16:19]

lgtm

[nyquist, 2015-09-04 22:16:41]

The CQ bit was checked by nyquist@chromium.org

[nyquist, 2015-09-04 22:16:41]

The patchset sent to the CQ was uploaded after l-g-t-m from agrieve@chromium.org
Link to the patchset: https://codereview.chromium.org/1311043014/#ps20001
(title: "Fixed rules.gni variable usage")

[commit-bot: I haz the power, 2015-09-04 22:16:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1311043014/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1311043014/20001

[commit-bot: I haz the power, 2015-09-04 23:10:00]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-04 23:10:43]

Patchset 2 (id:??) landed as
https://crrev.com/fbc342116e60698aae09bf4175a30bf8ccc14704
Cr-Commit-Position: refs/heads/master@{#347521}