SystemUI: Enable NFC tile

Author: Thecrazyskull <anaskarbila@gmail.com>
Date:   Tue Jan 17 10:56:39 2017 -0600

    SystemUI: Enable NFC tile

    Change-Id: Ib21f927d336fcb5e460552786828b79551b235fa

Author: inthewaves <inthewaves@pm.me>
Date:   Sun Sep 20 14:59:10 2020 -0700

    have NfcTile get an NfcAdapter directly

    This changes the NfcTile to not be dependent on an NfcManager giving the
    NfcTile an NfcAdapter.

    The problem with NfcTile is that the NfcService doesn't start until the
    device is unlocked after a reboot, but NfcTile can be created and have
    its state updated before the device is unlocked.

    The state of NfcTile depends on an NfcAdapter. The tile gets an
    NfcAdapter from a call to NfcAdapter#getDefaultAdapter, which gets an
    adapter from an NfcManager via Context#getSystemService, and NfcManager
    tries to get an adapter in its constructor via NfcAdapter#getNfcAdapter.

    If this is done before unlock, NfcService isn't started, so the
    constructor of NfcManager fails to get an adapter, opting to just store
    null. This means that the NfcManager that's _cached_ by the NfcTile's
    application context holds a null NfcAdapter, so subsequent calls in
    NfcTile to get the NfcAdapter will keep returning null.

    We can just have NfcTile get the NfcAdapter directly via
    NfcAdapter#getNfcAdapter instead of relying on an NfcManager to call the
    same method for us to get its default adapter. We just have to make sure
    we use the application context for NfcAdapter#getNfcAdapter, as per the
    doc comments for getNfcAdapter. This means that there's no longer an
    NfcManager associated with the NfcTile's application context.

    It doesn't look like NfcManager does anything special with the
    NfcAdapter anyway. It seems to just be some middle man for NfcAdapters:
    * The NfcAdapter field in NfcManager is final, and it doesn't do
    anything else with it besides have a getter method for returning it. The
    NfcManager seems to be a way to force third-party apps that want to get
    an NfcAdapter to use the application context.
    * NfcAdapter#getNfcAdapter manages the caching of NfcAdapters by
    application context in a static HashMap. NfcManager doesn't manage
    caching; it just calls NfcAdapter#getNfcAdapter.

    Change-Id: Ifafc666568a001a60baf7c8c16782dca1ee4d011

Author: Michael W <baddaemon87@gmail.com>
Date:   Fri Jan 15 00:03:02 2021 +0100

    NfcTile: Don't create an error when editing tiles

    Repro:
    * Make sure no NfcTile is in your expanded QS (not tested what happens if
      it's there)
    * Hit the Edit-button:

    Error in handleSetListeningInternal
    java.lang.IllegalArgumentException: Receiver not registered: com.android.systemui.qs.tiles.NfcTile$1@7c00b87
            at android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:1434)
            at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:1543)
            at android.content.ContextWrapper.unregisterReceiver(ContextWrapper.java:664)
            at com.android.systemui.qs.tiles.NfcTile.handleSetListening(NfcTile.java:64)
            at com.android.systemui.qs.tileimpl.QSTileImpl.handleSetListeningInternal(QSTileImpl.java:371)
            at com.android.systemui.qs.tileimpl.QSTileImpl.access$700(QSTileImpl.java:80)
            at com.android.systemui.qs.tileimpl.QSTileImpl$H.handleMessage(QSTileImpl.java:496)
            at android.os.Handler.dispatchMessage(Handler.java:107)
            at android.os.Looper.loop(Looper.java:214)
            at android.os.HandlerThread.run(HandlerThread.java:67)

    * Only register or unregister the receiver if we actually need to change
      registered-state
    * Same code is in AirPlaneModeToggle.java, presumably was also added to
      prevent unnecessary registering/unregistering

    Change-Id: I6cd8f9bffccb68596b736cc0a3a38e9c12b9c489

Change-Id: Ia06b923ee15e91a9c84a806d4c69755478df2063