Support for treating single party IMS conference as a standalone call.

Adding @hide APIs which Telephony can use to make a conference call with
a single participant look like its a standalone call.

Test: Manual testing
Bug: 75975913
Change-Id: Id8532234ab295785fc749b120898f43911e12637
diff --git a/telecomm/java/android/telecom/ConnectionService.java b/telecomm/java/android/telecom/ConnectionService.java
index 4c2d22f..82db0d2 100644
--- a/telecomm/java/android/telecom/ConnectionService.java
+++ b/telecomm/java/android/telecom/ConnectionService.java
@@ -1254,6 +1254,31 @@
                 mAdapter.removeExtras(id, keys);
             }
         }
+
+        @Override
+        public void onConferenceStateChanged(Conference c, boolean isConference) {
+            String id = mIdByConference.get(c);
+            if (id != null) {
+                mAdapter.setConferenceState(id, isConference);
+            }
+        }
+
+        @Override
+        public void onAddressChanged(Conference c, Uri newAddress, int presentation) {
+            String id = mIdByConference.get(c);
+            if (id != null) {
+                mAdapter.setAddress(id, newAddress, presentation);
+            }
+        }
+
+        @Override
+        public void onCallerDisplayNameChanged(Conference c, String callerDisplayName,
+                int presentation) {
+            String id = mIdByConference.get(c);
+            if (id != null) {
+                mAdapter.setCallerDisplayName(id, callerDisplayName, presentation);
+            }
+        }
     };
 
     private final Connection.Listener mConnectionListener = new Connection.Listener() {