AudioParameter: Document usage of exiting and closing.

Ensure only privileged access.
Log warning message on setParameters failure
to prevent entering standby silently.

Test: adb shell dumpsys media.audio_flinger
Bug: 73175392
Bug: 270480994
Bug: 279106598
Merged-In: Ie38ee93e98ff2164f9076b8b6b7831cc6b7a8896
Change-Id: Ie38ee93e98ff2164f9076b8b6b7831cc6b7a8896
diff --git a/media/libmediahelper/AudioParameter.cpp b/media/libmediahelper/AudioParameter.cpp
index 9a8156e..e25f9b7 100644
--- a/media/libmediahelper/AudioParameter.cpp
+++ b/media/libmediahelper/AudioParameter.cpp
@@ -32,6 +32,8 @@
 const char * const AudioParameter::keyFrameCount = AUDIO_PARAMETER_STREAM_FRAME_COUNT;
 const char * const AudioParameter::keyInputSource = AUDIO_PARAMETER_STREAM_INPUT_SOURCE;
 const char * const AudioParameter::keyScreenState = AUDIO_PARAMETER_KEY_SCREEN_STATE;
+const char * const AudioParameter::keyClosing = AUDIO_PARAMETER_KEY_CLOSING;
+const char * const AudioParameter::keyExiting = AUDIO_PARAMETER_KEY_EXITING;
 const char * const AudioParameter::keyBtNrec = AUDIO_PARAMETER_KEY_BT_NREC;
 const char * const AudioParameter::keyHwAvSync = AUDIO_PARAMETER_HW_AV_SYNC;
 const char * const AudioParameter::keyPresentationId = AUDIO_PARAMETER_STREAM_PRESENTATION_ID;
diff --git a/media/libmediahelper/include/media/AudioParameter.h b/media/libmediahelper/include/media/AudioParameter.h
index 41aff7c..6c34a4f 100644
--- a/media/libmediahelper/include/media/AudioParameter.h
+++ b/media/libmediahelper/include/media/AudioParameter.h
@@ -49,6 +49,12 @@
     static const char * const keyInputSource;
     static const char * const keyScreenState;
 
+    // TODO(b/73175392) consider improvement to AIDL StreamOut interface.
+    // keyClosing: "true" when AudioOutputDescriptor is closing.  Used by A2DP HAL.
+    // keyExiting: "1" on AudioFlinger Thread preExit.  Used by remote_submix and A2DP HAL.
+    static const char * const keyClosing;
+    static const char * const keyExiting;
+
     //  keyBtNrec: BT SCO Noise Reduction + Echo Cancellation parameters
     //  keyHwAvSync: get HW synchronization source identifier from a device
     //  keyMonoOutput: Enable mono audio playback