Add LIBMTP_Get_Thumbnail_Format to get thumbnail format of a file.
This CL is created for manually committing http://crrev.com/898023002.

BUG=451930
R=thestig@chromium.org

Review URL: https://codereview.chromium.org/900383002

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/libmtp@293974 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
5 files changed