[Android WebView] Add auto-grant permissions to WebViewShell.

[Android WebView] Add auto-grant permissions to WebViewShell.

Grant certain permissions like video and audio capture in the WebViewShell
mini-browser automatically. This is necessary to be able to test WebRTC
functionality.

BUG=481508
Committed: https://crrev.com/887a102d6acd7f0012b88605edb4eda8526e101d
Cr-Commit-Position: refs/heads/master@{#329647}

[timvolodine, 2015-05-13 14:21:08]

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

[timvolodine, 2015-05-13 15:08:17]

torne@: as you suggested I've uploaded a new patch with simplified logic for
granting requests.

[Torne, 2015-05-13 15:10:09]

lgtm

[timvolodine, 2015-05-13 16:03:19]

The CQ bit was checked by timvolodine@chromium.org

[commit-bot: I haz the power, 2015-05-13 16:05:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1127213005/20001

[commit-bot: I haz the power, 2015-05-13 16:11:11]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-13 16:12:12]

Patchset 2 (id:??) landed as
https://crrev.com/887a102d6acd7f0012b88605edb4eda8526e101d
Cr-Commit-Position: refs/heads/master@{#329647}