Move SkBitmapRegionCodec into client_utils/android

Bug: skia:10154

This will make it clear that these files are for Android use and
avoid compiling them for other clients.

Update testing tools to use android::skia::BitmapRegionDecoder, but
only if SK_ENABLE_ANDROID_UTILS is defined.

Take this opportunity to clean up the class:
- The base class, which was originally designed to allow switching
  amongst different implementations, is no longer needed. Rename
  SkBitmapRegionCodec to android::skia::BitmapRegionDecoder
  (following the new convention and matching the Java API name).
  Continue to inherit from SkBitmapRegionDecoder temporarily, to
  allow Android to switch to the new API.
- Use std::unique_ptr instead of passing raw pointers.

Add a test to verify that we only create a BitmapRegionDecoder if
it is one of the supported types.

Change-Id: Ied13fc8acb105fde042553331846d95ae15d6b57
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/287498
Commit-Queue: Leon Scroggins <scroggo@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
17 files changed