Remove android_webview_build completely.

Remove android_webview_build completely.

Remove the final remaining references to android_webview_build and
delete the variable itself from common.gypi and config.gni.

BUG=440793
Committed: https://crrev.com/62adf72afec378e8e22a8c3f549b86100ebfea2f
Cr-Commit-Position: refs/heads/master@{#325033}

[Torne, 2015-04-13 11:33:11]

torne@chromium.org changed reviewers:
+ cjhopman@chromium.org

[Torne, 2015-04-13 11:33:24]

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

[commit-bot: I haz the power, 2015-04-13 11:33:33]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1086583002/1

[commit-bot: I haz the power, 2015-04-13 11:41:44]

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

[commit-bot: I haz the power, 2015-04-13 11:41:44]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[cjhopman, 2015-04-13 21:15:01]

lgtm

[tfarina, 2015-04-13 21:20:35]

tfarina@chromium.org changed reviewers:
+ tfarina@chromium.org

[tfarina, 2015-04-13 21:20:36]

gn docs lgtm

[Torne, 2015-04-14 11:18:20]

The CQ bit was checked by torne@chromium.org

[commit-bot: I haz the power, 2015-04-14 11:18:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1086583002/1

[commit-bot: I haz the power, 2015-04-14 13:38:42]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-14 13:39:49]

Patchset 1 (id:??) landed as
https://crrev.com/62adf72afec378e8e22a8c3f549b86100ebfea2f
Cr-Commit-Position: refs/heads/master@{#325033}