Implement native compress API

Bug: 135133301
Test: Ifbcb41388a48afc64bb22623bb7e981b288b2457

Refactor the bulk of Bitmap_compress into hwui/Bitmap::compress, so that
it can be shared by the new API. Update its enum to match the proper
style. Also make the enum a class so it does not need to have a special
return value for a bad parameter, which is now handled by the caller.

Add ABitmap_compress, which implements the new API by calling
hwui/Bitmap::compress.

Change-Id: Ia8ba4c17b517a05b664c6e317e235836473fd7f6