ThreadSafeRefCountedGarbageCollected should use makeKeepAlive

ThreadSafeRefCountedGarbageCollected should use makeKeepAlive

Similar to RefCountedGarbageCollected, ThreadSafeRefCountedGarbageCollected
should use a helper method to create a self-keep-alive handle.
This change is to make it easier to blacklist a bad cast detected in UBSan.

BUG=405345
NOTRY=true

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180756

[haraken, 2014-08-22 00:05:11]

PTAL

[inferno, 2014-08-22 04:48:36]

The CQ bit was checked by inferno@chromium.org

[inferno, 2014-08-22 04:48:36]

lgtm

[commit-bot: I haz the power, 2014-08-22 04:49:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haraken@chromium.org/489353003/1

[commit-bot: I haz the power, 2014-08-22 05:48:27]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_chromium_gn_compile_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/android_chromium_gn_comp...)

[commit-bot: I haz the power, 2014-08-22 05:50:57]

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

[commit-bot: I haz the power, 2014-08-22 05:50:58]

Try jobs failed on following builders:
  android_chromium_gn_compile_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/android_chromium_gn_comp...)

[haraken, 2014-08-22 06:00:13]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2014-08-22 06:00:37]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haraken@chromium.org/489353003/1

[commit-bot: I haz the power, 2014-08-22 06:01:18]

Committed patchset #1 (1) as 180756