UpstreamNetworkMonitor is the part of tethering that files
NetworkRequests for upstream netwoks, but it currently does not
know all the requirements for upstream selection. For example, it
does not know whether automatic upstream selection is in use.
This forces the upstream selection code to be split between
UpstreamNetworkMonitor and Tethering. This makes it difficult to
follow.
This CL ensures that all information about upstream requirements
(DUN required, automatic upstream selection, tryCell) is passed
to UpstreamNetworkMonitor so it can be aware of it.
This CL also removes the ability for UpstreamNetworkMonitor's
callers to call registerMobileNetworkRequest or
releaseMobileNetworkRequest. In a future CL, this will be
automatically done by UpstreamNetworkMonitor depending on the
upstream requirements.
This CL is a no-op refactoring with no behaviour changes.
Bug: 173068192
Test: atest TetheringTests
Change-Id: I174f765c616e0dbe2aa493c12613e6131cff0666
0e7e32ab2c