Implement FrameInfo methods on AImageDecoder

Bug: 160984428
Test: If47d475233f6b9973abf68029b63a610ff47cdae

- AImageDecoder_getFrameInfo
- AImageDecoderFrameInfo_create
- AImageDecoderFrameInfo_delete
- AImageDecoderFrameInfo_getDuration
- AImageDecoderFrameInfo_getFrameRect
- AImageDecoderFrameInfo_getDisposeOp
- AImageDecoderFrameInfo_getBlendOp
- AImageDecoderFrameInfo_hasAlphaWithinBounds

These allow querying for information specific to a single frame in an
encoded image.

Change-Id: I6ce5665e9c25aed23f99ce88290e520d68fcb60e