GitLab

Prepare for removing mock framebuffers by moving the class into
MockDrmFramebufferGenerator. We don't need a mock framebuffer type.

Bug: 869206

Change-Id: I8a909d385f455fde0776e3cf5ad8d24791753e23
Reviewed-on: https://chromium-review.googlesource.com/1155913
Commit-Queue: Michael Spang <spang@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579586}