Remove SkBitmapRegionDecoder and SkBRDAllocator

Bug: skia:10154

Once ag/11371053 lands, Android will only be referencing the new version
at android::skia::BitmapRegionDecoder. Remove the old code that remained
for the transition.

Change-Id: Ic532d705e8f2861f56dcaa0ac1c68dd2b0712035
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291357
Commit-Queue: Leon Scroggins <scroggo@google.com>
Auto-Submit: Leon Scroggins <scroggo@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
7 files changed