API Documentation and Constant cleanup.

1. Update handover API docs for clarity.
2. Added an unknown value per API review comments.
3. Renamed HANDOVER_FAILURE_DEST_USER_REJECTED to
HANDOVER_FAILURE_USER_REJECTED
3. Removed the HANDOVER_FAILURE_DEST_INVALID_PERM constant since it isn't
used (methods which deal with permissions throw security exceptions).

Test: Make doc and verify documentation.
Change-Id: Id21d6b4c83d5c773ab38d78eb6b1886a1ac4dadf
Fixes: 73751004
Fixes: 73750515
Fixes: 73750817
diff --git a/telecomm/java/android/telecom/VideoProfile.java b/telecomm/java/android/telecom/VideoProfile.java
index e0e3a08..90ed36f 100644
--- a/telecomm/java/android/telecom/VideoProfile.java
+++ b/telecomm/java/android/telecom/VideoProfile.java
@@ -62,6 +62,7 @@
     @Retention(RetentionPolicy.SOURCE)
     @IntDef(
             flag = true,
+            prefix = { "STATE_" },
             value = {STATE_AUDIO_ONLY, STATE_TX_ENABLED, STATE_RX_ENABLED, STATE_BIDIRECTIONAL,
                     STATE_PAUSED})
     public @interface VideoState {}