Port enabling rtti for cfi.

Port enabling rtti for cfi.

Partially port https://codereview.chromium.org/1243373003/

BUG=chromium:515782
LOG=n
NOTRY=true

Committed: https://crrev.com/34ce987586bd74bd7d2f0c60d63420685b55c63e
Cr-Commit-Position: refs/heads/master@{#30497}

[Michael Achenbach, 2015-09-01 07:35:07]

machenbach@chromium.org changed reviewers:
+ bmeurer@chromium.org

[Michael Achenbach, 2015-09-01 07:35:37]

PTAL

[Benedikt Meurer, 2015-09-01 07:49:36]

LGTM.

[Michael Achenbach, 2015-09-01 08:01:28]

The CQ bit was checked by machenbach@chromium.org

[commit-bot: I haz the power, 2015-09-01 08:01:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1329553002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1329553002/1

[commit-bot: I haz the power, 2015-09-01 08:03:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-01 08:03:21]

Patchset 1 (id:??) landed as
https://crrev.com/34ce987586bd74bd7d2f0c60d63420685b55c63e
Cr-Commit-Position: refs/heads/master@{#30497}