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Add an overlay strategy that promotes a single quad to an
overlay iff the buffer that backs the quad can be directly used
as main framebuffer.

BUG=b/29430506
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel

Review-Url: https://codereview.chromium.org/2168693002
Cr-Commit-Position: refs/heads/master@{#406676}