Fix ChromeVox language switching on OOBE.

This cl requires a dependent fix in the NaCl tts engine extension.
https://chromium-review.googlesource.com/#/c/189510/

BUG=323712
TEST=Manually switch languages on OOBE; verify speech in target language occurs.

Review URL: https://codereview.chromium.org/190953011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256443 0039d316-1c4b-4281-b951-d872f2087c98
Removing the --gpu-swap-delay command line switch

BUG=350126

Review URL: https://codereview.chromium.org/195373003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256444 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256443
Fix to solve Chromecast rendering issues on OSX 10.6

Users are reporting a green screen is shown on the TV when
using Chromecast to mirroring a tab on OSX 10.6 with non-Intel
hardwares. Disabling asynchronous readback pixels solve
the problem.

BUG=348256

Review URL: https://codereview.chromium.org/183893035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256445 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256445