Fixed touch selection handle manipulation when pinched in.

Fixed touch selection handle manipulation when pinched in.

This patch applies the pinch viewport offset to selection handle
coordinates when passing the coordinates into Blink. This fixes the case
where selection handles would appear in the wrong place while being
manipulated while pinched in or when the ChromeOS on-screen keyboard is
showing.

BUG=376332

[bokan, 2014-06-04 22:37:12]

PTAL, thanks.

[aelias_OOO_until_Jul13, 2014-06-05 20:46:17]

lgtm

[bokan, 2014-06-05 20:49:33]

The CQ bit was checked by bokan@chromium.org

[commit-bot: I haz the power, 2014-06-05 20:50:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/bokan@chromium.org/319643002/20001

[commit-bot: I haz the power, 2014-06-05 22:08:01]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_blink_compile_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_compile_dbg/bu...)
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/10471)
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/10847)
  mac_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/mac_gpu/builds/13535)
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-06-05 22:08:20]

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

[commit-bot: I haz the power, 2014-06-05 22:08:21]

Try jobs failed on following builders:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[bokan, 2014-06-06 16:43:27]

The CQ bit was checked by bokan@chromium.org

[commit-bot: I haz the power, 2014-06-06 16:44:18]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/bokan@chromium.org/319643002/40001

[commit-bot: I haz the power, 2014-06-06 17:50:37]

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

[commit-bot: I haz the power, 2014-06-06 17:50:37]

Could not make sense out of svn commit message.