[FM] Fix Buganizer ID: 18456930  - FM radio audio got routed to loudspeaker unexpectedly

https://partner-android-review.git.corp.google.com/#/c/187894/

Change-Id: I3f9175bbc302e382155e568e66b88400ec05ffa5
Signed-off-by: Hochi Huang <hochi.huang@mediatek.com>
diff --git a/services/audiopolicy/AudioPolicyManager.h b/services/audiopolicy/AudioPolicyManager.h
index e2b6480..17348e9 100644
--- a/services/audiopolicy/AudioPolicyManager.h
+++ b/services/audiopolicy/AudioPolicyManager.h
@@ -722,7 +722,7 @@
         // if muting, wait for the audio in pcm buffer to be drained before proceeding
         // if unmuting, unmute only after the specified delay
         // Returns the number of ms waited
-        uint32_t  checkDeviceMuteStrategies(sp<AudioOutputDescriptor> outputDesc,
+        virtual uint32_t  checkDeviceMuteStrategies(sp<AudioOutputDescriptor> outputDesc,
                                             audio_devices_t prevDevice,
                                             uint32_t delayMs);