heif: fixes for image sequences and dual-function files

Adding support for two new sets of APIs on MediaMetadataRetriever:

- getImageAtIndex() and getPrimaryImage()
- getFrameAtIndex() and getFramesAtIndex()

Outline of changes:

- Proper indexing of all displayable still images, so that they
  can be retrieved by getImageAtIndex()

- Exposing still images as "image/x.android.heic" tracks in
  MediaExtractor with necessary descriptive keys (such as "grid-*")

- Support to retrieve video frames by absolute index instead
  of timestamps, as image use cases mostly are interested in
  getting the images and care less about timing.

- Support to retrieve video frames in batches because retrieving
  one frame at a time is inefficient.

- Refactor image / frame decoding code into FrameDecoder, and split
  still image decoding and video sequence decoding into to sub
  classes to facilite future development.

bug: 63633199

test:
cts-tradefed run cts-dev --module CtsMediaTestCases --compatibility:module-arg CtsMediaTestCases:include-annotation:android.platform.test.annotations.RequiresDevice

Change-Id: I2fe8519fb6907f315a8b513921fc1cc7f436e28d
diff --git a/media/libmediaplayerservice/MetadataRetrieverClient.h b/media/libmediaplayerservice/MetadataRetrieverClient.h
index c78cd4b..f71891a 100644
--- a/media/libmediaplayerservice/MetadataRetrieverClient.h
+++ b/media/libmediaplayerservice/MetadataRetrieverClient.h
@@ -52,6 +52,11 @@
     virtual status_t                setDataSource(const sp<IDataSource>& source, const char *mime);
     virtual sp<IMemory>             getFrameAtTime(
             int64_t timeUs, int option, int colorFormat, bool metaOnly);
+    virtual sp<IMemory>             getImageAtIndex(
+            int index, int colorFormat, bool metaOnly);
+    virtual status_t getFrameAtIndex(
+                std::vector<sp<IMemory> > *frames,
+                int frameIndex, int numFrames, int colorFormat, bool metaOnly);
     virtual sp<IMemory>             extractAlbumArt();
     virtual const char*             extractMetadata(int keyCode);