Revert of sRGB support in Ganesh. Several pieces: (patchset #12 id:220001 of https://codereview.chromium.org/1789663002/ )

Reason for revert:
We're getting sRGB non-8888 configs?

Original issue's description:
> sRGB support in Ganesh. Several pieces:
>
> sRGB support now also requires GL_EXT_texture_sRGB_decode, which allows
> us to disable sRGB -> Linear conversion when reading textures. This gives
> us an easy way to support "legacy" L32 mode. We disable decoding based on
> the pixel config of the render target. Textures can override that behavior
> (specifically for format-conversion draws where we want that behavior).
>
> Added sBGRA pixel config, which is not-really-a-format. It's just sRGBA
> internally, and the external format is BGR order, so TexImage calls will
> swizzle correctly. This lets us interact with sRGB raster surfaces on BGR
> platforms.
>
> Devices without sRGB support behave like they always have: conversion from
> color type and profile type ignores sRGB and always returns linear pixel
> configs.
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1789663002
>
> Committed: https://skia.googlesource.com/skia/+/9e3f1bf4e5cd8fc59554f986f36d6b034e99f9eb

TBR=reed@google.com,bsalomon@google.com,robertphillips@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1814533003
29 files changed