Move ContentAppModelBuilder to athena/extensions.

Move ContentAppModelBuilder to athena/extensions.

The AppModelBuilder does not rely on content so much, rather
it's highly related to the extension system. Therefore, it's
better to be in athena/extensions, and its name should be
ExtensionAppModelBuilder instead.

This will simplifies DEPS rules of athena/content.

BUG=None
R=oshima@chromium.org
TBR=yoz@chromium.org, xiyuan@chromium.org, tony@chromium.org
TEST=build

Committed: https://crrev.com/1fed1b5fe736ea42a505a0b54445e86f8f195f33
Cr-Commit-Position: refs/heads/master@{#294011}

[oshima, 2014-09-06 00:19:04]

nice. 

can you clean up a/e/chrome/DEPS and a/e/shell/DEPS?
then lgtm

[Jun Mukai, 2014-09-06 00:43:13]

On 2014/09/06 00:19:04, oshima wrote:
> nice. 
> 
> can you clean up a/e/chrome/DEPS and a/e/shell/DEPS?
> then lgtm

Done.  a/e/shell/DEPS doesn't have to be cleaned up.

[Jun Mukai, 2014-09-06 00:43:15]

The CQ bit was checked by mukai@chromium.org

[commit-bot: I haz the power, 2014-09-06 00:43:49]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mukai@chromium.org/543263002/20001

[commit-bot: I haz the power, 2014-09-06 01:03:02]

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

[commit-bot: I haz the power, 2014-09-06 01:03:03]

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

[Jun Mukai, 2014-09-06 01:30:02]

mukai@chromium.org changed reviewers:
+ tony@chromium.org, xiyuan@chromium.org, yoz@chromium.org

[Jun Mukai, 2014-09-06 01:30:24]

TBR for the OWNERS of moved DEPS entries

[Jun Mukai, 2014-09-06 01:30:30]

The CQ bit was checked by mukai@chromium.org

[commit-bot: I haz the power, 2014-09-06 01:32:02]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mukai@chromium.org/543263002/20001

[commit-bot: I haz the power, 2014-09-06 01:55:18]

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

[commit-bot: I haz the power, 2014-09-06 01:55:19]

Try jobs failed on following builders:
  ios_dbg_simulator on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)
  ios_rel_device on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device/bu...)
  ios_rel_device_ninja on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)

[Jun Mukai, 2014-09-09 17:41:49]

The CQ bit was checked by mukai@chromium.org

[commit-bot: I haz the power, 2014-09-09 17:42:44]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mukai@chromium.org/543263002/20001

[commit-bot: I haz the power, 2014-09-09 17:50:27]

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

[commit-bot: I haz the power, 2014-09-09 17:50:29]

Try jobs failed on following builders:
  ios_rel_device_ninja on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)

[Jun Mukai, 2014-09-09 20:01:28]

The CQ bit was checked by mukai@chromium.org

[commit-bot: I haz the power, 2014-09-09 20:14:21]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mukai@chromium.org/543263002/40001

[commit-bot: I haz the power, 2014-09-09 21:27:19]

Committed patchset #3 (id:40001) as 2d8d918ed36cac532e6139482eab843bf07583ea

[commit-bot: I haz the power, 2014-09-10 03:55:43]

Patchset 3 (id:??) landed as
https://crrev.com/1fed1b5fe736ea42a505a0b54445e86f8f195f33
Cr-Commit-Position: refs/heads/master@{#294011}