Create xxxhdpi density splits when density splits are enabled

Create xxxhdpi density splits when density splits are enabled

The xxxhdpi density was missed in the initial implementation of density
splits.

BUG=488324
Committed: https://crrev.com/aa50092a84c19942281fbf8f3a7dc1d67e9a34bb
Cr-Commit-Position: refs/heads/master@{#335534}

[agrieve, 2015-06-19 02:17:35]

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

[cjhopman, 2015-06-19 22:58:23]

lgtm

[agrieve, 2015-06-19 23:42:38]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-06-19 23:43:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1192263002/1

[commit-bot: I haz the power, 2015-06-19 23:49:24]

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

[commit-bot: I haz the power, 2015-06-19 23:49:25]

Try jobs failed on following builders:
  linux_chromium_compile_dbg_32_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  ios_dbg_simulator_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)
  ios_rel_device_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)
  mac_chromium_compile_dbg_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[agrieve, 2015-06-22 16:45:24]

The CQ bit was checked by agrieve@chromium.org

[agrieve, 2015-06-22 16:45:24]

The patchset sent to the CQ was uploaded after l-g-t-m from
cjhopman@chromium.org
Link to the patchset: https://codereview.chromium.org/1192263002/#ps20001
(title: "rebased")

[commit-bot: I haz the power, 2015-06-22 16:45:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1192263002/20001

[commit-bot: I haz the power, 2015-06-22 18:50:38]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-22 18:51:30]

Patchset 2 (id:??) landed as
https://crrev.com/aa50092a84c19942281fbf8f3a7dc1d67e9a34bb
Cr-Commit-Position: refs/heads/master@{#335534}