PPC: Reland "Merge old data and pointer space."

PPC: Reland "Merge old data and pointer space."

Port 59be4ba7f4f70dedcaac60914adaa2885a3da5d0

Original commit message:
This reverts commit cbfcee557503514bef20abdfc78ceb262c9c4d64.

R=mbrandy@us.ibm.com

BUG=

Committed: https://crrev.com/ae475b54c9d35a61cc4013147a66884d95cea240
Cr-Commit-Position: refs/heads/master@{#27723}

[michael_dawson, 2015-04-09 19:58:53]

michael_dawson@ca.ibm.com changed reviewers:
+ mbrandy@us.ibm.com

[michael_dawson, 2015-04-09 19:59:07]

Catching up next PPC port

[MTBrandyberry, 2015-04-09 20:00:06]

On 2015/04/09 19:59:07, michael_dawson wrote:
> Catching up next PPC port

lgtm

[michael_dawson, 2015-04-09 21:20:32]

The CQ bit was checked by michael_dawson@ca.ibm.com

[commit-bot: I haz the power, 2015-04-09 21:20:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1074953002/1

[commit-bot: I haz the power, 2015-04-09 21:45:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-09 21:46:01]

Patchset 1 (id:??) landed as
https://crrev.com/ae475b54c9d35a61cc4013147a66884d95cea240
Cr-Commit-Position: refs/heads/master@{#27723}