Use heif embedded thumbnail if available

Add plumbing to retieve the embedded thumbnail from
MPEG4Extractor/ItemTable.

bug: 74395267
Test: CTS MediaMetadataRetriever test; manual test of thumbnail
extraction by browsing new folders containing heif files in
Downloads app.
Change-Id: Ic49f6dfa47eddc229b9f4b0e1835d58df1dce9f8
diff --git a/media/libmediaplayerservice/MetadataRetrieverClient.h b/media/libmediaplayerservice/MetadataRetrieverClient.h
index f71891a..e774c8f 100644
--- a/media/libmediaplayerservice/MetadataRetrieverClient.h
+++ b/media/libmediaplayerservice/MetadataRetrieverClient.h
@@ -53,7 +53,7 @@
     virtual sp<IMemory>             getFrameAtTime(
             int64_t timeUs, int option, int colorFormat, bool metaOnly);
     virtual sp<IMemory>             getImageAtIndex(
-            int index, int colorFormat, bool metaOnly);
+            int index, int colorFormat, bool metaOnly, bool thumbnail);
     virtual status_t getFrameAtIndex(
                 std::vector<sp<IMemory> > *frames,
                 int frameIndex, int numFrames, int colorFormat, bool metaOnly);