MediaMetrics: Add const correctness for items in service

Allows multithreaded use of items without lock.

Test: mediametrics dumpsys, atest mediametrics_tests
Bug: 138583596
Change-Id: Ieb901076b9acc33a89737b320a4fc8ce82f2608d
diff --git a/services/mediaanalytics/statsd_extractor.cpp b/services/mediaanalytics/statsd_extractor.cpp
index d84930c..55d5c29 100644
--- a/services/mediaanalytics/statsd_extractor.cpp
+++ b/services/mediaanalytics/statsd_extractor.cpp
@@ -37,7 +37,7 @@
 
 namespace android {
 
-bool statsd_extractor(MediaAnalyticsItem *item)
+bool statsd_extractor(const MediaAnalyticsItem *item)
 {
     if (item == NULL) return false;