Set camera parameters continuous focus mode on

Android Video Capture: Set continuous focus mode on in cam parameters.

This is, apparently, needed for macro modes, although
autofocus seems to work ok in general.

BUG=343894
TEST=Please refer to the bug, basically a gUM() + close QR codes focus test.

Committed: https://crrev.com/667e79783dd2bbd413b165abfd7fae2bfa3210d5
Cr-Commit-Position: refs/heads/master@{#304909}

[mcasas, 2014-11-19 19:50:57]

mcasas@chromium.org changed reviewers:
+ qinmin@chromium.org

[mcasas, 2014-11-19 19:50:57]

qinmin@ FYI/RFC :)

[qinmin, 2014-11-19 21:27:44]

lgtm

[mcasas, 2014-11-19 22:00:56]

The CQ bit was checked by mcasas@chromium.org

[commit-bot: I haz the power, 2014-11-19 22:01:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/737003003/1

[commit-bot: I haz the power, 2014-11-19 22:42:40]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-19 22:45:16]

Patchset 1 (id:??) landed as
https://crrev.com/667e79783dd2bbd413b165abfd7fae2bfa3210d5
Cr-Commit-Position: refs/heads/master@{#304909}

[tommi (sloooow) - chröme, 2014-11-20 14:15:15]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/740363002/ by tommi@chromium.org.

The reason for reverting is: Looks like this is causing
MANUAL_CanAcquireVgaOnRealWebcam to fail..