Report result SKIPPED in ConnDiags if the network is not validated.

This CL updates ConnectivityDiagnostics to report
NETWORK_VALIDATION_RESULT_SKIPPED when the platform does not validate
the reported Network. This CL also updates the behavior for
ConnectivityManager#reportNetworkConnectivity, such that it will always
generate a ConnectivityReport on the reported network. If the reported
connectivity does not match the known connectivity of this network, the
network is revalidated and a report is generated. Otherwise,
revalidation is not performed and the cached ConnectivityReport is sent
instead.

This CL also updates ConnDiags behavior for calls to
ConnectivityManager#reportNetworkConnectivity. Specifically, ConnDiags
callbacks are only notified for these calls if:
  a) the call causes the Network to be re-validated, or
  b) the callback registrant was the caller of
     #reportNetworkConnectivity().
For b), the caller is always guaranteed to receive a ConnectivityReport
(a fresh report if the Network is re-validated, else the cached report).

Bug: 162407730
Test: atest FrameworksNetTests ConnectivityDiagnosticsManagerTest
Change-Id: I78b78919d5b0f09348dfdd5fdb37418b8c7f861f

0 files changed, 0 insertions, 0 deletions