aaudio: fix some state transitions

Now requestStop() and requestPause() do the appropriate thing
based on state.
Flush is allowed when OPEN, PAUSED or STOPPED because there might
be pre-roll data.

Bug: 69810494
Test: test_various.cpp
Change-Id: Ie1b306b17734a58fa71b1742bb186482893656b7
diff --git a/media/libaaudio/src/legacy/AudioStreamTrack.cpp b/media/libaaudio/src/legacy/AudioStreamTrack.cpp
index 4d1b187..ee069ee 100644
--- a/media/libaaudio/src/legacy/AudioStreamTrack.cpp
+++ b/media/libaaudio/src/legacy/AudioStreamTrack.cpp
@@ -287,13 +287,8 @@
     if (mAudioTrack.get() == nullptr) {
         ALOGE("requestPause() no AudioTrack");
         return AAUDIO_ERROR_INVALID_STATE;
-    } else if (getState() != AAUDIO_STREAM_STATE_STARTING
-            && getState() != AAUDIO_STREAM_STATE_STARTED) {
-            // TODO What about DISCONNECTED?
-        ALOGE("requestPause(), called when state is %s",
-              AAudio_convertStreamStateToText(getState()));
-        return AAUDIO_ERROR_INVALID_STATE;
     }
+
     setState(AAUDIO_STREAM_STATE_PAUSING);
     mAudioTrack->pause();
     mCallbackEnabled.store(false);
@@ -308,10 +303,8 @@
     if (mAudioTrack.get() == nullptr) {
         ALOGE("requestFlush() no AudioTrack");
         return AAUDIO_ERROR_INVALID_STATE;
-    } else if (getState() != AAUDIO_STREAM_STATE_PAUSED) {
-        ALOGE("requestFlush() not paused");
-        return AAUDIO_ERROR_INVALID_STATE;
     }
+
     setState(AAUDIO_STREAM_STATE_FLUSHING);
     incrementFramesRead(getFramesWritten() - getFramesRead());
     mAudioTrack->flush();
@@ -325,6 +318,7 @@
         ALOGE("requestStop() no AudioTrack");
         return AAUDIO_ERROR_INVALID_STATE;
     }
+
     setState(AAUDIO_STREAM_STATE_STOPPING);
     incrementFramesRead(getFramesWritten() - getFramesRead()); // TODO review
     mTimestampPosition.set(getFramesWritten());