Implement Observe Mode and Preferred Service event listeners with
functional callbacks.

Bug: 356447790
Test: CTS tests
Flag: android.nfc.Flags.nfcEventListener

Change-Id: I66acbe5d1e41f30149e98f13d2374841d4b1604d
diff --git a/nfc/api/current.txt b/nfc/api/current.txt
index 96b7c13..00812042 100644
--- a/nfc/api/current.txt
+++ b/nfc/api/current.txt
@@ -207,6 +207,7 @@
     method public boolean isDefaultServiceForCategory(android.content.ComponentName, String);
     method @FlaggedApi("android.nfc.enable_card_emulation_euicc") public boolean isEuiccSupported();
     method public boolean registerAidsForService(android.content.ComponentName, String, java.util.List<java.lang.String>);
+    method @FlaggedApi("android.nfc.nfc_event_listener") public void registerNfcEventListener(@NonNull java.util.concurrent.Executor, @NonNull android.nfc.cardemulation.CardEmulation.NfcEventListener);
     method @FlaggedApi("android.nfc.nfc_read_polling_loop") public boolean registerPollingLoopFilterForService(@NonNull android.content.ComponentName, @NonNull String, boolean);
     method @FlaggedApi("android.nfc.nfc_read_polling_loop") public boolean registerPollingLoopPatternFilterForService(@NonNull android.content.ComponentName, @NonNull String, boolean);
     method public boolean removeAidsForService(android.content.ComponentName, String);
@@ -216,6 +217,7 @@
     method public boolean setPreferredService(android.app.Activity, android.content.ComponentName);
     method @FlaggedApi("android.nfc.nfc_observe_mode") public boolean setShouldDefaultToObserveModeForService(@NonNull android.content.ComponentName, boolean);
     method public boolean supportsAidPrefixRegistration();
+    method @FlaggedApi("android.nfc.nfc_event_listener") public void unregisterNfcEventListener(@NonNull android.nfc.cardemulation.CardEmulation.NfcEventListener);
     method @NonNull @RequiresPermission(android.Manifest.permission.NFC) public boolean unsetOffHostForService(@NonNull android.content.ComponentName);
     method public boolean unsetPreferredService(android.app.Activity);
     field @Deprecated public static final String ACTION_CHANGE_DEFAULT = "android.nfc.cardemulation.action.ACTION_CHANGE_DEFAULT";
@@ -233,13 +235,16 @@
     field public static final int SELECTION_MODE_PREFER_DEFAULT = 0; // 0x0
   }
 
+  @FlaggedApi("android.nfc.nfc_event_listener") public static interface CardEmulation.NfcEventListener {
+    method @FlaggedApi("android.nfc.nfc_event_listener") public default void onObserveModeStateChanged(boolean);
+    method @FlaggedApi("android.nfc.nfc_event_listener") public default void onPreferredServiceChanged(boolean);
+  }
+
   public abstract class HostApduService extends android.app.Service {
     ctor public HostApduService();
     method public final void notifyUnhandled();
     method public final android.os.IBinder onBind(android.content.Intent);
     method public abstract void onDeactivated(int);
-    method @FlaggedApi("android.nfc.nfc_event_listener") public void onObserveModeStateChanged(boolean);
-    method @FlaggedApi("android.nfc.nfc_event_listener") public void onPreferredServiceChanged(boolean);
     method public abstract byte[] processCommandApdu(byte[], android.os.Bundle);
     method @FlaggedApi("android.nfc.nfc_read_polling_loop") public void processPollingFrames(@NonNull java.util.List<android.nfc.cardemulation.PollingFrame>);
     method public final void sendResponseApdu(byte[]);