MediaMetrics: Add thread-safety checking

Test: atest mediametrics_tests
Bug: 70398235
Bug: 149850236
Change-Id: I288ef92e6444785e02043c2629355c229c14e85c
diff --git a/media/libmediametrics/Android.bp b/media/libmediametrics/Android.bp
index 0cd5194..03068c7 100644
--- a/media/libmediametrics/Android.bp
+++ b/media/libmediametrics/Android.bp
@@ -22,9 +22,11 @@
     export_include_dirs: ["include"],
 
     cflags: [
-        "-Werror",
-        "-Wno-error=deprecated-declarations",
         "-Wall",
+        "-Werror",
+        "-Wextra",
+        "-Wthread-safety",
+        "-Wunreachable-code",
     ],
 
     sanitize: {