Always accelerate canvases by default

Effectively remove size and readback heuristics from acceleration
logic. This improves performance, simplifies testing and will
eventually simplify the code as well. For now quite a few tests need
to change as their small canvases are now accelerated.

CrElementsFingerprintProgressArcTest and
FileManagerJsTest.ImageOrientatio need to explicitly turn on pixel
output. It's off by default for browsertests and is required for
pixel readback from the gpu.

WebRtcCaptureFromElementBrowserTest.CaptureFromOpaqueCanvas2DHandlesContextLoss
does not yet support accelerated canvases, so mark as failing for
now. https://crbug.com/954142

The following 3 tests need to be rebaselined due to small anti-aliasing
difference:
Pixel_CanvasLowLatency2D
Pixel_CSSFilterEffects
Pixel_CSSFilterEffects_NoOverlays

Pixel_CanvasDisplayLinearRGBAccelerated2D was never actually using an
accelerated canvas due to the size heuristic.

yuv-video-on-accelerated-canvas.html was testing behaviour specifically
based on the idea that smaller canvases will be unaccelerated. Since
this is no longer true, this test is no longer valid.

Bug: 909937
Change-Id: Ia0c654ac3154b5840193e12b6e8b63a04e9db26e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1486711
Commit-Queue: Aaron Krajeski <aaronhk@chromium.org>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654210}
18 files changed