AudioAudioPolicyFocusListener and ducking enforced by framework

Notify AudioPolicyFocusListener an app received
  AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK even when focus is enforced by
  the framework.

Test: see bug
Bug: 37241497
Change-Id: I569e6611fb398955adbcd5bbfbda9d44db4aa729
(cherry picked from commit 081249282005640682da315d6f0e0e3697fe4b37)
diff --git a/services/core/java/com/android/server/audio/FocusRequester.java b/services/core/java/com/android/server/audio/FocusRequester.java
index 73cbffd..f6fc724 100644
--- a/services/core/java/com/android/server/audio/FocusRequester.java
+++ b/services/core/java/com/android/server/audio/FocusRequester.java
@@ -381,6 +381,8 @@
                         Log.v(TAG, "NOT dispatching " + focusChangeToString(mFocusLossReceived)
                             + " to " + mClientId + ", ducking implemented by framework");
                     }
+                    mFocusController.notifyExtPolicyFocusLoss_syncAf(
+                            toAudioFocusInfo(), false /* wasDispatched */);
                     return; // with mFocusLossWasNotified = false
                 }