Remove android_webview_build conditions.

Remove android_webview_build conditions.

Remove references to android_webview_build now that we no longer support
that build configuration. This also removes use_system_stlport which was
only supported with android_webview_build.

BUG=chromium:440793
LOG=n

Committed: https://crrev.com/5d56277e8f1bd9a444f88fa9d57857bb6a81770c
Cr-Commit-Position: refs/heads/master@{#27708}

[Torne, 2015-04-08 09:10:59]

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

[Jakob Kummerow, 2015-04-09 13:11:05]

LGTM.

[Torne, 2015-04-09 13:11:26]

The CQ bit was checked by torne@chromium.org

[commit-bot: I haz the power, 2015-04-09 13:11:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1069663002/1

[commit-bot: I haz the power, 2015-04-09 13:38:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-09 13:38:32]

Patchset 1 (id:??) landed as
https://crrev.com/5d56277e8f1bd9a444f88fa9d57857bb6a81770c
Cr-Commit-Position: refs/heads/master@{#27708}