Remove never-happen if statement in WebExternalTextureLayerImpl.

Remove never-happen if statement in WebExternalTextureLayerImpl.

Now this condition never happens after r287686 and BUG=344393
r287686 got rid of lost_resource from this condition.
BUG=344393
made a client never destructed before releasing all mailboxes.

BUG=344393
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288157

[dshwang, 2014-08-07 15:32:31]

Hi, could you review?
It's follow-up cl of
https://codereview.chromium.org/369823002
https://codereview.chromium.org/169933002

[enne (OOO), 2014-08-07 17:03:34]

lgtm

[dshwang, 2014-08-07 17:42:17]

The CQ bit was checked by dongseong.hwang@intel.com

[dshwang, 2014-08-07 17:42:36]

On 2014/08/07 17:03:34, enne wrote:
> lgtm

Thank you for quick review.

[commit-bot: I haz the power, 2014-08-07 17:56:43]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dongseong.hwang@intel.com/451723002/1

[commit-bot: I haz the power, 2014-08-07 18:57:10]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win8_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_rel...)
  win_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel/...)
  win_chromium_x64_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[commit-bot: I haz the power, 2014-08-07 22:53:22]

Change committed as 288157