chrome: Ozone Aura needs the newly global extension commands also.

The offending CL https://codereview.chromium.org/23812010 has introduced
changes that break Ozone platform support. This CL make the necessary changes,
moving the Aura X11 specific code to be now compiled with generic Aura
solutions as well.

In particular, this brings back support for Chrome browser in Ozone-Wayland.

BUG=302437

Review URL: https://codereview.chromium.org/26539009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229865 0039d316-1c4b-4281-b951-d872f2087c98
Extension docs: Remove the remaining references to experimental_debugger.

R=mkearney@chromium.org
TBR=mpcomplete@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/33153002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229866 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229866