MediaMetrics: Misc fixes

Remove unneeded headers from MediaMetricsItem.
Optimize map writes with emplace_hint.

Test: atest mediametrics_tests
Bug: 149850236
Change-Id: Ice6fddb8402a5ccbf1df6e6e02fa4aae4c1b42d5
diff --git a/media/libmediametrics/MediaMetricsItem.cpp b/media/libmediametrics/MediaMetricsItem.cpp
index 4371668..7cdbe5f 100644
--- a/media/libmediametrics/MediaMetricsItem.cpp
+++ b/media/libmediametrics/MediaMetricsItem.cpp
@@ -25,6 +25,7 @@
 #include <set>
 
 #include <binder/Parcel.h>
+#include <cutils/properties.h>
 #include <utils/Errors.h>
 #include <utils/Log.h>
 #include <utils/SortedVector.h>
diff --git a/media/libmediametrics/include/media/MediaMetricsItem.h b/media/libmediametrics/include/media/MediaMetricsItem.h
index 8477f8d..303343f 100644
--- a/media/libmediametrics/include/media/MediaMetricsItem.h
+++ b/media/libmediametrics/include/media/MediaMetricsItem.h
@@ -27,12 +27,8 @@
 #include <variant>
 
 #include <binder/Parcel.h>
-#include <cutils/properties.h>
 #include <utils/Errors.h>
-#include <utils/KeyedVector.h>
-#include <utils/RefBase.h>
-#include <utils/StrongPointer.h>
-#include <utils/Timers.h>
+#include <utils/Timers.h> // nsecs_t
 
 namespace android {