API declarations for Call Handover.

Design doc:
https://docs.google.com/document/d/1qY3oAzjff_4A1ttYb_CGrE_OwTRmXMG_KGsIuPT1ey8/edit#

Bug: 65415068
Test: manual.
Change-Id: I0c2f561d92ad6504f858eadde09980fc1ce8727f
diff --git a/telecomm/java/android/telecom/TelecomManager.java b/telecomm/java/android/telecom/TelecomManager.java
index aa2323d..4d2cb04 100644
--- a/telecomm/java/android/telecom/TelecomManager.java
+++ b/telecomm/java/android/telecom/TelecomManager.java
@@ -1749,6 +1749,41 @@
         return false;
     }
 
+    /**
+     * Called from the recipient side of a handover to indicate a desire to accept the handover
+     * of an ongoing call to another {@link ConnectionService} identified by
+     * {@link PhoneAccountHandle} destAcct. For managed {@link ConnectionService}s, the specified
+     * {@link PhoneAccountHandle} must have been registered with {@link #registerPhoneAccount} and
+     * the user must have enabled the corresponding {@link PhoneAccount}.  This can be checked using
+     * {@link #getPhoneAccount}. Self-managed {@link ConnectionService}s must have
+     * {@link android.Manifest.permission#MANAGE_OWN_CALLS} to handover a call to it.
+     * <p>
+     * Once invoked, this method will cause the system to bind to the {@link ConnectionService}
+     * associated with the {@link PhoneAccountHandle} destAcct and call
+     * (See {@link ConnectionService#onCreateIncomingHandoverConnection}).
+     * <p>
+     * For a managed {@link ConnectionService}, a {@link SecurityException} will be thrown if either
+     * the {@link PhoneAccountHandle} destAcct does not correspond to a registered
+     * {@link PhoneAccount} or the associated {@link PhoneAccount} is not currently enabled by the
+     * user.
+     * <p>
+     * For a self-managed {@link ConnectionService}, a {@link SecurityException} will be thrown if
+     * the calling app does not have {@link android.Manifest.permission#MANAGE_OWN_CALLS}.
+     *
+     * @param srcAddr The {@link android.net.Uri} of the ongoing call to handover to the caller’s
+     *                {@link ConnectionService}.
+     * @param videoState Video state after the handover.
+     * @param destAcct The {@link PhoneAccountHandle} registered to the calling package.
+     */
+    public void acceptHandover(Uri srcAddr, int videoState, PhoneAccountHandle destAcct) {
+        try {
+            if (isServiceConnected()) {
+                getTelecomService().acceptHandover(srcAddr, videoState, destAcct);
+            }
+        } catch (RemoteException e) {
+            Log.e(TAG, "RemoteException acceptHandover: " + e);
+        }
+    }
 
     private ITelecomService getTelecomService() {
         if (mTelecomServiceOverride != null) {