GitLab

The WebKit/Source/modules/vr/ code uses gfx::GpuMemoryBufferHandle and
gpu::MailboxHolder for transferring frame images, these symbols
shouldn't block presubmit checks.

BUG=763980

Change-Id: I2f9fdd173f0173bdb51337d3943b590f42550528
Reviewed-on: https://chromium-review.googlesource.com/804742
Commit-Queue: Klaus Weidner <klausw@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521636}