AXScrollbar should not be recreated right after removal

Fix leaking AXScrollbar

AXScrollbar was being recreated right after it has been removed, causing it to leak.

Test will be added in https://codereview.chromium.org/1202263005/
BUG=502782
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197754

[keishi, 2015-06-24 11:38:39]

keishi@chromium.org changed reviewers:
+ dmazzoni@chromium.org, haraken@chromium.org

[haraken, 2015-06-24 11:51:02]

LGTM

[dmazzoni, 2015-06-24 14:21:22]

The CQ bit was checked by dmazzoni@chromium.org

[dmazzoni, 2015-06-24 14:21:23]

lgtm

[commit-bot: I haz the power, 2015-06-24 14:21:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1203903003/1

[commit-bot: I haz the power, 2015-06-24 14:31:03]

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

[commit-bot: I haz the power, 2015-06-24 14:31:04]

Try jobs failed on following builders:
  mac_blink_compile_dbg on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/mac_blink_compile_dbg/bu...)

[keishi, 2015-06-24 15:07:41]

The CQ bit was checked by keishi@chromium.org

[keishi, 2015-06-24 15:07:41]

The patchset sent to the CQ was uploaded after l-g-t-m from
haraken@chromium.org, dmazzoni@chromium.org
Link to the patchset: https://codereview.chromium.org/1203903003/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-06-24 15:08:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1203903003/20001

[commit-bot: I haz the power, 2015-06-24 16:15:43]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197754