aaudio: lock transport methods

The start/pause/stop/flush/close and other binder methods
need to be thread safe. They do not need to run
in parallel. So a lock was added for each.

Where virtual methods are needed, the locked method calls
a corresponding _l submethod, eg. stop() calls stop_l().

The close logic was also simplified because the "pending"
technique is not needed now that we have the locks.
It was only needed because a close could have occured
while in the middle of another method.

This CL was merged with changes in RVC-DEV.

Bug: 153358911
Test: adb logcat *:F
Test: in another window:  test_binder_attack
Test: There should be no fatal error in the logcat.
Test: atest CtsNativeMediaAAudioTestCases
Change-Id: I5920cf78af4501856756c5c2fc8e77758232508a
diff --git a/services/oboeservice/AAudioServiceEndpointShared.cpp b/services/oboeservice/AAudioServiceEndpointShared.cpp
index 21253c8..dc21886 100644
--- a/services/oboeservice/AAudioServiceEndpointShared.cpp
+++ b/services/oboeservice/AAudioServiceEndpointShared.cpp
@@ -168,13 +168,11 @@
 
 aaudio_result_t AAudioServiceEndpointShared::stopStream(sp<AAudioServiceStreamBase> sharedStream,
                                                         audio_port_handle_t clientHandle) {
-    // Don't lock here because the disconnectRegisteredStreams also uses the lock.
-
     // Ignore result.
     (void) getStreamInternal()->stopClient(clientHandle);
 
     if (--mRunningStreamCount == 0) { // atomic
-        stopSharingThread();
+        stopSharingThread(); // the sharing thread locks mLockStreams
         getStreamInternal()->requestStop();
     }
     return AAUDIO_OK;