Open 4G+ file by using AppFuse.

To open files by using AppFuse, the provider needs to know the size of
file. Previously we cannot open 4G+ files because we cannot obtain file
size for such large files.

Now MtpDatabase contains correct size for 4GB+ file size. The CL starts
opening files by using AppFuse which obtains partial bytes by using
getObjectPartial64 operation.

FIXED=26840097

Change-Id: I1cb41972175c2b98f4aa76981decc6b3ad35486d