aaudio: add thread safety annotation

Also improve naming to clarify lock requirements.

And call some locked methods that were not called before.
Although they were protected with a different lock so
it should have no effect.

Bug: 171296283
Test: adb logcat *:F
Test: In another window:
Test: atest AAudioTestCases
Change-Id: I6e863cbdea9250188e3f4b8f8654ef71c8951e74
diff --git a/services/oboeservice/AAudioServiceEndpointShared.h b/services/oboeservice/AAudioServiceEndpointShared.h
index 91a86c1..8357567 100644
--- a/services/oboeservice/AAudioServiceEndpointShared.h
+++ b/services/oboeservice/AAudioServiceEndpointShared.h
@@ -20,6 +20,8 @@
 #include <atomic>
 #include <mutex>
 
+#include <android-base/thread_annotations.h>
+
 #include "AAudioServiceEndpoint.h"
 #include "client/AudioStreamInternal.h"
 #include "client/AudioStreamInternalPlay.h"
@@ -63,7 +65,7 @@
 
 protected:
 
-    aaudio_result_t          startSharingThread_l();
+    aaudio_result_t          startSharingThread_l() REQUIRES(mLockStreams);
 
     aaudio_result_t          stopSharingThread();