libchromeos: Allow chunked HTTP uploads when data size is unknown

When uploading data from a stream of unknown size (e.g. a compressed
stream), switch to using "chunked" transfer encoding to allow pure
streaming data uploading.

BUG=brillo:1185
TEST=`FEATURES=test emerge-link libchromeos`

Change-Id: Iadecdd44ae38b587e701208cd8b2d6940ab68742
Reviewed-on: https://chromium-review.googlesource.com/275280
Trybot-Ready: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Nathan Bullock <nathanbullock@google.com>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
3 files changed