DO NOT MERGE Add capability to determine if downgrade to audio is denied.

By default we assume downgrade to audio is permitted; this capability
probides a means for a carrier to specifically deny that.

Bug: 22728624

Change-Id: I75e0a5b9e5ad2d970003a4691b6fc0ac0dcfe9e0
diff --git a/api/current.txt b/api/current.txt
index e29d5ec..3691270 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -30003,6 +30003,7 @@
     method public static boolean hasProperty(int, int);
     method public boolean hasProperty(int);
     method public static java.lang.String propertiesToString(int);
+    field public static final int CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO = 4194304; // 0x400000
     field public static final int CAPABILITY_CAN_PAUSE_VIDEO = 1048576; // 0x100000
     field public static final int CAPABILITY_DISCONNECT_FROM_CONFERENCE = 8192; // 0x2000
     field public static final int CAPABILITY_HOLD = 1; // 0x1
@@ -30142,6 +30143,7 @@
     method public final void setVideoProvider(android.telecom.Connection.VideoProvider);
     method public final void setVideoState(int);
     method public static java.lang.String stateToString(int);
+    field public static final int CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO = 8388608; // 0x800000
     field public static final int CAPABILITY_CAN_PAUSE_VIDEO = 1048576; // 0x100000
     field public static final int CAPABILITY_CAN_UPGRADE_TO_VIDEO = 524288; // 0x80000
     field public static final int CAPABILITY_DISCONNECT_FROM_CONFERENCE = 8192; // 0x2000
diff --git a/api/system-current.txt b/api/system-current.txt
index 47aeee3..b09a4a2 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -32179,6 +32179,7 @@
     method public static boolean hasProperty(int, int);
     method public boolean hasProperty(int);
     method public static java.lang.String propertiesToString(int);
+    field public static final int CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO = 4194304; // 0x400000
     field public static final int CAPABILITY_CAN_PAUSE_VIDEO = 1048576; // 0x100000
     field public static final int CAPABILITY_DISCONNECT_FROM_CONFERENCE = 8192; // 0x2000
     field public static final int CAPABILITY_HOLD = 1; // 0x1
@@ -32329,6 +32330,7 @@
     method public final void setVideoProvider(android.telecom.Connection.VideoProvider);
     method public final void setVideoState(int);
     method public static java.lang.String stateToString(int);
+    field public static final int CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO = 8388608; // 0x800000
     field public static final int CAPABILITY_CAN_PAUSE_VIDEO = 1048576; // 0x100000
     field public static final int CAPABILITY_CAN_UPGRADE_TO_VIDEO = 524288; // 0x80000
     field public static final int CAPABILITY_DISCONNECT_FROM_CONFERENCE = 8192; // 0x2000
diff --git a/telecomm/java/android/telecom/Call.java b/telecomm/java/android/telecom/Call.java
index 6511705..270c8ce 100644
--- a/telecomm/java/android/telecom/Call.java
+++ b/telecomm/java/android/telecom/Call.java
@@ -24,7 +24,6 @@
 import java.lang.String;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -210,7 +209,22 @@
          * Call sends responses through connection.
          * @hide
          */
-        public static final int CAPABILITY_CAN_SEND_RESPONSE_VIA_CONNECTION = 0x00400000;
+        public static final int CAPABILITY_CAN_SEND_RESPONSE_VIA_CONNECTION = 0x00200000;
+
+        /**
+         * When set, prevents a video {@code Call} from being downgraded to an audio-only call.
+         * <p>
+         * Should be set when the VideoState has the {@link VideoProfile#STATE_TX_ENABLED} or
+         * {@link VideoProfile#STATE_RX_ENABLED} bits set to indicate that the connection cannot be
+         * downgraded from a video call back to a VideoState of
+         * {@link VideoProfile#STATE_AUDIO_ONLY}.
+         * <p>
+         * Intuitively, a call which can be downgraded to audio should also have local and remote
+         * video
+         * capabilities (see {@link #CAPABILITY_SUPPORTS_VT_LOCAL_BIDIRECTIONAL} and
+         * {@link #CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL}).
+         */
+        public static final int CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO = 0x00400000;
 
         //******************************************************************************************
         // Next CAPABILITY value: 0x00800000
@@ -327,6 +341,9 @@
             if (can(capabilities, CAPABILITY_SUPPORTS_VT_REMOTE_TX)) {
                 builder.append(" CAPABILITY_SUPPORTS_VT_REMOTE_TX");
             }
+            if (can(capabilities, CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO)) {
+                builder.append(" CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO");
+            }
             if (can(capabilities, CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL)) {
                 builder.append(" CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL");
             }
diff --git a/telecomm/java/android/telecom/Connection.java b/telecomm/java/android/telecom/Connection.java
index 4115756..c9fc51e 100644
--- a/telecomm/java/android/telecom/Connection.java
+++ b/telecomm/java/android/telecom/Connection.java
@@ -255,8 +255,23 @@
      */
     public static final int CAPABILITY_CAN_SEND_RESPONSE_VIA_CONNECTION = 0x00400000;
 
+    /**
+     * When set, prevents a video call from being downgraded to an audio-only call.
+     * <p>
+     * Should be set when the VideoState has the {@link VideoProfile#STATE_TX_ENABLED} or
+     * {@link VideoProfile#STATE_RX_ENABLED} bits set to indicate that the connection cannot be
+     * downgraded from a video call back to a VideoState of
+     * {@link VideoProfile#STATE_AUDIO_ONLY}.
+     * <p>
+     * Intuitively, a call which can be downgraded to audio should also have local and remote
+     * video
+     * capabilities (see {@link #CAPABILITY_SUPPORTS_VT_LOCAL_BIDIRECTIONAL} and
+     * {@link #CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL}).
+     */
+    public static final int CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO = 0x00800000;
+
     //**********************************************************************************************
-    // Next CAPABILITY value: 0x00800000
+    // Next CAPABILITY value: 0x01000000
     //**********************************************************************************************
 
     /**
@@ -371,6 +386,9 @@
         if (can(capabilities, CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL)) {
             builder.append(" CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL");
         }
+        if (can(capabilities, CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO)) {
+            builder.append(" CAPABILITY_CANNOT_DOWNGRADE_VIDEO_TO_AUDIO");
+        }
         if (can(capabilities, CAPABILITY_HIGH_DEF_AUDIO)) {
             builder.append(" CAPABILITY_HIGH_DEF_AUDIO");
         }