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/AAudioClientTracker.h b/services/oboeservice/AAudioClientTracker.h
index facfc3b..2b38621 100644
--- a/services/oboeservice/AAudioClientTracker.h
+++ b/services/oboeservice/AAudioClientTracker.h
@@ -21,6 +21,7 @@
 #include <mutex>
 #include <set>
 
+#include <android-base/thread_annotations.h>
 #include <utils/Singleton.h>
 
 #include <aaudio/AAudio.h>
@@ -114,10 +115,12 @@
     };
 
     // This must be called under mLock
-    android::sp<NotificationClient> getNotificationClient_l(pid_t pid);
+    android::sp<NotificationClient> getNotificationClient_l(pid_t pid)
+            REQUIRES(mLock);
 
     mutable std::mutex                               mLock;
-    std::map<pid_t, android::sp<NotificationClient>> mNotificationClients;
+    std::map<pid_t, android::sp<NotificationClient>> mNotificationClients
+            GUARDED_BY(mLock);
     android::AAudioService                          *mAAudioService = nullptr;
 };