Linux: fix XRENDER support for NX
Linux: fix XRENDER support for NX

The NX X server doesn't support xRGB32 XRENDER picture formats. So, if
we don't find one of those formats, fall back on ARGB32, which is
fine, except that the X server will spend time dealing with an alpha
channel which is all 254 or 255. ARGB32 support is required by the
XRENDER spec.

(This doesn't fix VNC, a patch for that is forthcoming.)

Review URL: http://codereview.chromium.org/28192


git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@10484 0039d316-1c4b-4281-b951-d872f2087c98

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