MTP: Implement GetThumb command

This allows the PC to access thumbnails in JPEG files over MTP/PTP

Bug: 3219495

Change-Id: I4964f8b4826dffb7f0f77464ec91bd2e97a2f007
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/media/mtp/MtpDatabase.h b/media/mtp/MtpDatabase.h
index d7bde00..4e6ac7a 100644
--- a/media/mtp/MtpDatabase.h
+++ b/media/mtp/MtpDatabase.h
@@ -84,6 +84,8 @@
     virtual MtpResponseCode         getObjectInfo(MtpObjectHandle handle,
                                             MtpObjectInfo& info) = 0;
 
+    virtual void*                   getThumbnail(MtpObjectHandle handle, size_t& outThumbSize) = 0;
+
     virtual MtpResponseCode         getObjectFilePath(MtpObjectHandle handle,
                                             MtpString& outFilePath,
                                             int64_t& outFileLength,