Remove isShareable from BitmapRegionDecoder

Bug: 140600285
Test: CtsGraphicsTestCases:android.graphics.cts.BitmapRegionDecoderTest
Test: I684e0ed6049e146e2c1698383c73709a7163b642

Clean up BRD in preparation for mainline module changes.
isShareable has been ignored for a long time, so update the APIs to
reflect that. Deprecate the existing ones, and add replacements without
isShareable. Make newInstance(FileDescriptor, boolean) into
newInstance(ParcelFileDescriptor), as recommended by the build failure.
- newInstance(byte[], int, int, boolean) has ignored it since
I7dd545c9d52d21c226e11b8921e35a1d9bba9515 (GB)
- newInstance(FileDescriptor, boolean) has ignored it since
Id1e1c8c5938ee1a33c6fa3caabd2c28e89243eb4 (KITKAT)
- newInstance(InputStream, boolean) and newInstance(String, boolean)
have always ignored it

Document WebP and HEIF support.

Add @NonNull annotations. Remove misleading comments about
returning null on failure. My understanding is that if it either returns
an object or throws an Exception, @NonNull is the appropriate
annotation - the client does not need to check for null.

Change-Id: I0bf8c4c72cc118d2799a59e8eb6c2cede546fceb