GitLab

This CL enables SkiaRenderer to use Windows DC layer overlays. The
operation is essentially the same as GLRenderer with some minor
differences.

The list of DCLayerOverlay candidates is plumbed to the GPU thread via
ScheduleGpuTask() instead of over command buffer. Also instead of
providing a GL texture ID a gpu::Mailbox is provided.

DCLayerOverlayProcessor::ProcessForUnderlay() is modified to set to
SharedQuadState::are_contents_opaque true for the replacement
SolidColorDrawQuad. SkiaRenderer needs to draw the replacement quad with
SkBlendMode::kSrc but setting the blend mode to kSrc isn't supported by
GLRenderer. SkiaRenderer uses the |are_contents_opaque| to change the
blend mode at draw time while GLRenderer ignores it.

SkiaOutputSurface::SkiaSwapBuffers() is also modified to optionally
return a SyncToken. This SyncToken can be used to return overlay
resources after swap buffers completes on the GPU thread. This should
work for all overlay paths except macOS.

Bug: 1003040
Change-Id: I9ff3ff55cde1aabfae8200fc2dfcc416c15d0005
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1796626Reviewed-by: weiliangc <weiliangc@chromium.org>
Reviewed-by: Vasiliy Telezhnikov <vasilyt@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Commit-Queue: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697751}