Use single return to break bubble of RTT chat.

Also change "done" button to "send" in input box and disallow multiple line since return will be interpreted as "send".

Bug: 67596257
Test: manual
PiperOrigin-RevId: 189409725
Change-Id: I3d3bf3e11cd04d6689125399f4567e88ee3f28f0
diff --git a/java/com/android/incallui/rtt/impl/RttChatFragment.java b/java/com/android/incallui/rtt/impl/RttChatFragment.java
index dd55ccf..90bf199 100644
--- a/java/com/android/incallui/rtt/impl/RttChatFragment.java
+++ b/java/com/android/incallui/rtt/impl/RttChatFragment.java
@@ -206,7 +206,7 @@
 
   @Override
   public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
-    if (actionId == EditorInfo.IME_ACTION_DONE) {
+    if (actionId == EditorInfo.IME_ACTION_SEND) {
       submitButton.performClick();
       return true;
     }
diff --git a/java/com/android/incallui/rtt/impl/res/layout/frag_rtt_chat.xml b/java/com/android/incallui/rtt/impl/res/layout/frag_rtt_chat.xml
index 7531179..34a9954 100644
--- a/java/com/android/incallui/rtt/impl/res/layout/frag_rtt_chat.xml
+++ b/java/com/android/incallui/rtt/impl/res/layout/frag_rtt_chat.xml
@@ -48,9 +48,8 @@
         android:paddingEnd="16dp"
         android:background="@drawable/input_bubble_background"
         android:hint="@string/rtt_input_hint"
-        android:imeOptions="actionDone"
-        android:inputType="textMultiLine|text"
-        android:maxLines="4"
+        android:imeOptions="actionSend"
+        android:inputType="text"
         android:minHeight="53dp"
         android:textColor="#DD000000"
         android:textColorHint="#757575"
diff --git a/java/com/android/incallui/rtt/protocol/Constants.java b/java/com/android/incallui/rtt/protocol/Constants.java
index 5806bba..1c13b07 100644
--- a/java/com/android/incallui/rtt/protocol/Constants.java
+++ b/java/com/android/incallui/rtt/protocol/Constants.java
@@ -20,5 +20,5 @@
 public interface Constants {
 
   /** String used to break bubble, which means one RTT message is complete. */
-  String BUBBLE_BREAKER = "\n\n";
+  String BUBBLE_BREAKER = "\n";
 }