Add OnSetWarningAndLimit into TestableNetworkStatsProvider

This change also address left comments at ag/15010113.

Ignore-AOSP-First: Counter part CL is not in aosp.
Test: m gts && atest \
      GtsNetworkStackHostTestCases:NetworkStatsHostTest#testNetworkStatsProvider
Bug: 191327585
Change-Id: I100668cc6d4cecbaff29d027d37d313dd48854f3
1 file changed
tree: 3f5b54103e01f91652c826cc46c9be999459efce
  1. client-libs/
  2. common/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING