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After https://codereview.chromium.org/2789363004 landed, Ozone Drm
supports the KMS "rotation" property that can be used to set a transform
to HW overlays.

This CL relaxes the transform restrictions of the fullscreen and
single on top overlay strategies.

Additionally, it makes sure that any configuration containing a transform
will be reject if the legacy page flip is being used.

After this CL WebGL and Pepper content can be promoted to HW overlay when
backed by a Gpu Memory Buffer.

BUG=b/36752417
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2794343003
Cr-Commit-Position: refs/heads/master@{#467697}