Revert of Use SkBitmapCache to optimize readPixels on a texture-backed bitmap (patchset #6 id:100001 of https://codereview.chromium.org/533323002/)

Reason for revert:
Component inversions in Blink's printing/webgl-repeated-printing.html: https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/24033/layout-test-results/printing/webgl-repeated-printing-diff.txt

Reverting to unblock rolls.

Original issue's description:
> Use SkBitmapCache to optimize readPixels on a texture-backed bitmap
>
> BUG=skia:2786
>
> Committed: https://skia.googlesource.com/skia/+/95fd68e5ccd242a91e6dd827dd695f18661efbe6

R=junov@chromium.org, reed@google.com, bsalomon@google.com, piotaixr@chromium.org
TBR=bsalomon@google.com, junov@chromium.org, piotaixr@chromium.org, reed@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2786

Author: fmalita@chromium.org

Review URL: https://codereview.chromium.org/551523003
1 file changed