Update Docs to clarify using a Message across IPC

When using Message across IPC, the message must be sent
with a Messenger. Update Docs to reflect this.

Bug: 77870347
Test: Telephony Unit Tests
Merged-In: Ie1a0be63d26136f14cd30c354b889ec0311cc7ee
Change-Id: I27977a13f7ccb6875b5fdb7eb6c6836a84166eeb

2 files changed, 28 insertions, 4 deletions

diff --git a/telephony/java/android/telephony/ims/feature/MmTelFeature.java b/telephony/java/android/telephony/ims/feature/MmTelFeature.java
index f12540f8dd13..bc790fb0a6e6 100644
--- a/telephony/java/android/telephony/ims/feature/MmTelFeature.java
+++ b/telephony/java/android/telephony/ims/feature/MmTelFeature.java
@@ -18,7 +18,6 @@ package android.telephony.ims.feature;
 
 import android.annotation.IntDef;
 import android.annotation.SystemApi;
-import android.net.Uri;
 import android.os.Bundle;
 import android.os.Message;
 import android.os.RemoteException;
@@ -644,7 +643,19 @@ public class MmTelFeature extends ImsFeature {
      *         {@link TelecomManager#TTY_MODE_FULL},
      *         {@link TelecomManager#TTY_MODE_HCO},
      *         {@link TelecomManager#TTY_MODE_VCO}
-     * @param onCompleteMessage A {@link Message} to be used when the mode has been set.
+     * @param onCompleteMessage If non-null, this MmTelFeature should call this {@link Message} when
+     *         the operation is complete by using the associated {@link android.os.Messenger} in
+     *         {@link Message#replyTo}. For example:
+     * {@code
+     *     // Set UI TTY Mode and other operations...
+     *     try {
+     *         // Notify framework that the mode was changed.
+     *         Messenger uiMessenger = onCompleteMessage.replyTo;
+     *         uiMessenger.send(onCompleteMessage);
+     *     } catch (RemoteException e) {
+     *         // Remote side is dead
+     *     }
+     * }
      */
     public void setUiTtyMode(int mode, Message onCompleteMessage) {
         // Base Implementation - Should be overridden
diff --git a/telephony/java/android/telephony/ims/stub/ImsCallSessionImplBase.java b/telephony/java/android/telephony/ims/stub/ImsCallSessionImplBase.java
index 7b9fe2b144ab..da6a7a60c3b3 100644
--- a/telephony/java/android/telephony/ims/stub/ImsCallSessionImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/ImsCallSessionImplBase.java
@@ -30,8 +30,6 @@ import com.android.ims.internal.IImsCallSession;
 import com.android.ims.internal.IImsVideoCallProvider;
 import android.telephony.ims.ImsVideoCallProvider;
 
-import dalvik.system.CloseGuard;
-
 /**
  * Base implementation of IImsCallSession, which implements stub versions of the methods available.
  *
@@ -510,6 +508,21 @@ public class ImsCallSessionImplBase implements AutoCloseable {
      * and event flash to 16. Currently, event flash is not supported.
      *
      * @param c the DTMF to send. '0' ~ '9', 'A' ~ 'D', '*', '#' are valid inputs.
+     * @param result If non-null, the {@link Message} to send when the operation is complete. This
+     *         is done by using the associated {@link android.os.Messenger} in
+     *         {@link Message#replyTo}. For example:
+     * {@code
+     *     // Send DTMF and other operations...
+     *     try {
+     *         // Notify framework that the DTMF was sent.
+     *         Messenger dtmfMessenger = result.replyTo;
+     *         if (dtmfMessenger != null) {
+     *             dtmfMessenger.send(result);
+     *         }
+     *     } catch (RemoteException e) {
+     *         // Remote side is dead
+     *     }
+     * }
      */
     public void sendDtmf(char c, Message result) {
     }