GitLab

CommitSurfaceHierarchy() moves pending_frame_callbacks_ into
frame_callbacks_ before calling UpdateSurface() so that the ack doesn't
arrive too early.

exo::Surface is the only class which needs
MojoCompositorFrameSinkClient::WillDrawSurface(). With this change, we
can remove WillDrawSurface from the mojo interface and reduce IPC overhead.

BUG=671202, 709076

Review-Url: https://codereview.chromium.org/2786643002
Cr-Commit-Position: refs/heads/master@{#462678}