On D3D11, if dcomp.dll can be loaded then EGL_ANGLE_direct_composition
is exposed. Setting EGL_DIRECT_COMPOSITION_ANGLE as an attrib on a
surface will force it to use DirectComposition to draw to the screen,
possibly saving power.

BUG=524838

Change-Id: I3ea175a97bbca1a3388ffe52fdd1587a2f0c2ce7
Reviewed-on: https://chromium-review.googlesource.com/319214Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: John Bauman <jbauman@chromium.org>