TokenWatcher.acquire() synchronizes on mTokens, not this, so we need to synchronize on mKeyguardDisabled in disableKeyguard() to synchronize properly with reenableKeyguard(). This should fix b/2180142 (Stuck in enable keyguard when receiving phone call) Change-Id: Iad66a2748c7fbf2c516fdb8a00988696719ea80c Signed-off-by: Mike Lockwood <lockwood@android.com>