cc: Fix bug in generating picture layer pairs from 2 lists.

cc: Fix bug in generating picture layer pairs from 2 lists.

When splitting the picture pile list on LayerTreeHostImpl up into a
list on each LayerTreeImpl, a bug was introduced in the pair gathering
code.

If a layer is not in the RSLL on the active tree, we need to still
generate a pair for the pending twin if it is in the RSLL, so that we
will raster the layer and block activation on it.

R=enne, vmpstr
BUG=458411
NOTRY=true

Committed: https://crrev.com/7e094504b6010caa1e17ccd526738c374366f81f
Cr-Commit-Position: refs/heads/master@{#316327}

[vmpstr, 2015-02-13 21:15:22]

lgtm, thanks!

[danakj, 2015-02-13 21:30:54]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2015-02-13 21:31:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/926023003/20001

[commit-bot: I haz the power, 2015-02-13 22:38:46]

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

[commit-bot: I haz the power, 2015-02-13 22:38:47]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[danakj, 2015-02-13 22:40:16]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2015-02-13 22:40:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/926023003/20001

[danakj, 2015-02-13 23:34:59]

The CQ bit was unchecked by danakj@chromium.org

[danakj, 2015-02-13 23:35:06]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2015-02-13 23:36:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/926023003/20001

[commit-bot: I haz the power, 2015-02-13 23:38:07]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-13 23:38:59]

Patchset 2 (id:??) landed as
https://crrev.com/7e094504b6010caa1e17ccd526738c374366f81f
Cr-Commit-Position: refs/heads/master@{#316327}