fix DownloadThread's use of ETag, range headers

DownloadThread was only maintaining ETag and the file size for the
duration of one HTTP request, rather than over all the requests needed
to fetch a file, which kind of defeats the point of having them.  Fix
this by moving several state variables from InnerState to State, and
initializing the total bytes and current bytes values from the
download database.

Skip actually making the HTTP request if we've already downloaded all
the bytes of the file.  This works around bug 5217390 by making the
second DownloadThread do nothing instead of trying to fetch past the
end of the file.  (A real fix would eliminate the race condition that
causes the second thread to get created in the first place.)

Bug: 5217390
Change-Id: Ib5b8f87398b4ed2cb3d7f09569e245b55a89da5a

0 files changed, 0 insertions, 0 deletions