Reland "Move SkFrontBufferedStream into Android-only dir"

This reverts commit b25f30348bfee972b509fd4a13a0de99e89caa6a.

Bug: skia:10154

Original message:
> Add client_utils for code that is specifically for a single client.
> Move SkFrontBufferedStream into its android/ subdir. Rename the class
> to android::skia::FrontBufferedStream. Temporarily leave in
> SkFrontBufferedStream until Android updates to the new API.
>
> Add a new optional target for client_utils/android. It is built in dev
> builds for testing, and when building for the Android framework.

Deliberately do not include client_utils in Google3, since the whole
point is to only include where necessary.

Change-Id: I48938c56aabb98e1ed820240d43ffcd0fdce7956
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/285104
Commit-Queue: Leon Scroggins <scroggo@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index 921883e..ad63cfc 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -8,6 +8,10 @@
 
   * <insert new release note here>
 
+  * Add the new directory client_utils/ for code that is specific to a single client and
+    should be considered separate from Skia proper. Move SkFrontBufferedStream into the
+    subdir android/.
+
   * SkBitmap and SkPixmap's erase() methods now treat their color parameters
     consistently with the rest of Skia, with all SkColors and any untagged
     SkColor4fs interpreted as sRGB, not as a color in the bitmap's color space.