aaudio: use xruns detected in the service

The service knows when an actual xrun occurs so we pass
that value to the client.

Bug: 38512417
Test: write_sine_callback -pl -n1 -s20 -c2 -u
Change-Id: I9e5ff1edd2e9378957309280162d7cda855f5adb
diff --git a/services/oboeservice/AAudioServiceEndpointShared.cpp b/services/oboeservice/AAudioServiceEndpointShared.cpp
index 820ed28..6af9e7e 100644
--- a/services/oboeservice/AAudioServiceEndpointShared.cpp
+++ b/services/oboeservice/AAudioServiceEndpointShared.cpp
@@ -47,6 +47,7 @@
            << std::setfill('0') << std::setw(8)
            << std::hex << mStreamInternal->getServiceHandle()
            << std::dec << std::setfill(' ');
+    result << ", XRuns = " << mStreamInternal->getXRunCount();
     result << "\n";
     result << "    Running Stream Count: " << mRunningStreamCount << "\n";