APM: use dock device for volume when dock device is selected.

Bug: 262415494
Test: make
Change-Id: I5b5e7fc98805485e4e9e16d005678d6af1724d14
diff --git a/services/audiopolicy/common/include/policy.h b/services/audiopolicy/common/include/policy.h
index de8e77f..d266e63 100644
--- a/services/audiopolicy/common/include/policy.h
+++ b/services/audiopolicy/common/include/policy.h
@@ -218,12 +218,15 @@
         return *(deviceTypes.begin());
     } else {
         // Multiple device selection is either:
+        //  - dock + one other device: give priority to dock in this case.
         //  - speaker + one other device: give priority to speaker in this case.
         //  - one A2DP device + another device: happens with duplicated output. In this case
         // retain the device on the A2DP output as the other must not correspond to an active
         // selection if not the speaker.
         //  - HDMI-CEC system audio mode only output: give priority to available item in order.
-        if (deviceTypes.count(AUDIO_DEVICE_OUT_SPEAKER) != 0) {
+        if (deviceTypes.count(AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET) != 0) {
+            return AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET;
+        } else if (deviceTypes.count(AUDIO_DEVICE_OUT_SPEAKER) != 0) {
             return AUDIO_DEVICE_OUT_SPEAKER;
         } else if (deviceTypes.count(AUDIO_DEVICE_OUT_SPEAKER_SAFE) != 0) {
             return AUDIO_DEVICE_OUT_SPEAKER_SAFE;