Replace OffscreenCanvasSurfaceClient with DisplayCompositorClient

This is part of moving OffscreenCanvas into new display compositor.

BUG=686861,664547
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2695603002
Cr-Commit-Position: refs/heads/master@{#450534}
12 files changed