11392 Wire up software rendering in the test compositor.

11394 Avoid root surface acquisition during custom composition with software renderer.

11395 Remove deprecated ThreadTest::GetThreadTaskRunner and use the newer CreateNewThread API.

11416 Shrink cirrus docker image: reduce RUN count, apt-get clean

11419 Support non-60 refresh rate on PerformanceOverlay

11420 Fix touchpad scrolling on Chromebook

11423 Add tracing of the number of frames in flight in the pipeline.

11427 Skip empty platform view overlays.

11436 update method for skia

11456 Update the ui.LineMetrics.height metric to be more useful to external users

11473 Add missing newline at EOF