WebGPUSwapBufferProvider: unflip cc:TextureLayer

WebGPU produces non-Y-flipped (texel coord +Y = screen -Y = up) textures. SetFlipped(false) on
the cc::TextureLayer so that it renders right-side-up (texel coord +Y = screen +Y = down).

Context:
https://dawn-review.googlesource.com/c/dawn/+/8420/6/src/dawn_native/metal/RenderPipelineMTL.mm#285

Bug: dawn:43
Change-Id: Ic630af4140e5944945fc24e1d3bc16316c920b2f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1682839
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#675364}