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>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index de45307..8f2eb25 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -9,6 +9,8 @@
 
   * <insert new release notes here>
 
+  * Move SkBitmapRegionDecoder into client_utils/android.
+
   * Remove SkSurface::MakeFromBackendTextureAsRenderTarget.
     This factory existed to work around issues with GL_TEXTURE_RECTANGLE that existed
     in Chrome's command buffer. Those issues have since been resolved. Use