UBSAN fixes.

Make UBSAN vptr work inside UBSAN and also add the UNDEFINED_SANITIZER define. Also, these can share the same blacklist file due to seperate prefixes.

TBR=glider@chromium.org,jochen@chromium.org
BUG=

Committed: https://crrev.com/ac18f489dca8c902e4dfaa1a28d716b7914121d0
Cr-Commit-Position: refs/heads/master@{#312207}

[inferno, 2015-01-16 20:56:11]

inferno@chromium.org changed reviewers:
+ jochen@chromium.org

[Martin Barbella, 2015-01-16 21:01:20]

LGTM

[inferno, 2015-01-16 21:01:35]

The CQ bit was checked by inferno@chromium.org

[commit-bot: I haz the power, 2015-01-16 21:02:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/851163006/1

[commit-bot: I haz the power, 2015-01-16 22:07:59]

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

[commit-bot: I haz the power, 2015-01-16 22:08:00]

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

[inferno, 2015-01-16 22:09:29]

The CQ bit was checked by inferno@chromium.org

[commit-bot: I haz the power, 2015-01-16 22:09:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/851163006/1

[commit-bot: I haz the power, 2015-01-16 22:10:27]

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

[commit-bot: I haz the power, 2015-01-16 22:10:28]

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

[Alexander Potapenko, 2015-01-19 12:34:24]

LGTM

[jochen (gone - plz use gerrit), 2015-01-20 15:50:11]

lgtm

[inferno, 2015-01-20 16:15:14]

The CQ bit was checked by inferno@chromium.org

[commit-bot: I haz the power, 2015-01-20 16:15:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/851163006/1

[commit-bot: I haz the power, 2015-01-20 16:16:17]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-20 16:17:23]

Patchset 1 (id:??) landed as
https://crrev.com/ac18f489dca8c902e4dfaa1a28d716b7914121d0
Cr-Commit-Position: refs/heads/master@{#312207}