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This change with allow me to cleanly add interfaces to the GL implementations.
The intent is to add interfaces to the different components, but these get lost
in the flat client/ directory. Moving display related files to their own location.

R=yuweih@chromium.org
BUG=671692

Review-Url: https://codereview.chromium.org/2614443003
Cr-Commit-Position: refs/heads/master@{#441727}