Add toFloat*Array() methods and use them in layout tests.

Add toFloat*Array() methods and use them in layout tests.

The methods return the serialized 16 elements m11 to m44 of the current
matrix in column-major order.

The specification:
  http://dev.w3.org/fxtf/geometry/

Intent to Implement:
  https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/V_bJNtOg0oM

BUG=388780
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180827

[zino, 2014-08-18 05:07:28]

PTAL

[Rik, 2014-08-22 09:09:54]

lgtm

[krit, 2014-08-22 09:26:09]

lgtm

[zino, 2014-08-24 05:59:09]

The CQ bit was checked by jinho.bang@samsung.com

[commit-bot: I haz the power, 2014-08-24 06:00:13]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jinho.bang@samsung.com/483633002/20001

[commit-bot: I haz the power, 2014-08-24 06:49:46]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  blink_presubmit on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/blink_presubmit/builds/1...)
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/2...)
  linux_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/2...)
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/20937)
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/24112)
  linux_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/linux_gpu_trigger...)

[commit-bot: I haz the power, 2014-08-24 06:51:46]

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

[commit-bot: I haz the power, 2014-08-24 06:51:46]

Try jobs failed on following builders:
  blink_presubmit on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/blink_presubmit/builds/1...)

[zino, 2014-08-24 06:54:52]

The CQ bit was checked by jinho.bang@samsung.com

[commit-bot: I haz the power, 2014-08-24 06:55:23]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jinho.bang@samsung.com/483633002/20001

[zino, 2014-08-24 06:58:04]

The CQ bit was unchecked by jinho.bang@samsung.com

[zino, 2014-08-24 06:58:07]

The CQ bit was checked by jinho.bang@samsung.com

[commit-bot: I haz the power, 2014-08-24 06:58:15]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jinho.bang@samsung.com/483633002/20001

[commit-bot: I haz the power, 2014-08-24 07:58:05]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/24117)

[commit-bot: I haz the power, 2014-08-24 08:32:43]

Committed patchset #2 (20001) as 180827