exo::CompositorFrameSink uses CompositorFrameSinkHolder* instead of mojo interface pointer

This fixes the performance regression on arm devices.

BUG=680066

Review-Url: https://codereview.chromium.org/2626293005
Cr-Commit-Position: refs/heads/master@{#443712}
6 files changed