tree 73351de4af5b43ce4fe5beda97b22ed4d1530b65
parent 7d76682bb3a3aaf0d6adec10014a18bebbd4a061
author Christopher Wiley <wiley@google.com> 1464716675 -0700
committer Christopher Wiley <wiley@google.com> 1465497794 -0700

Fix race conditions between Tethering and TetherInterfaceStateMachine

( cherry-pick of de4819dc82b734036b22416228327d2712e01884 )

Previously, Tethering would answer requests for current tethering state
by calling methods on instances of TetherInterfaceStateMachine to build
up that state. This is incorrect, since state queries can come in on an
arbitrary thread, independent of updates to the state machines
instances.

Fix this by:
  - Altering TetherInterfaceStateMachine to push consistent state
    snapshots to Tethering via notifyInterfaceStateChange()
  - Storing the last state snapshot in Tethering.mTetherStates
  - Removing public methods to query TetherInterfaceStateMachine state.
  - Consistently synchronizing access to Tethering.mTetherStates

Bug: 29009601
Test: WiFi Tethering continues to work, unittests continue to pass

Change-Id: Ied334f5e8739bc3aff1b08a1079095b9cc2a7958