Enable UMA histogram logger for low memor kill events in ArcMetricsService.

components/arc/metrics/arc_metrics_service.cc

Index: components/arc/metrics/arc_metrics_service.cc
diff --git a/components/arc/metrics/arc_metrics_service.cc b/components/arc/metrics/arc_metrics_service.cc
index 208e8210fa06b85449e8f986e826e6e046bc3f08..b158f0eb40b57d32a9d0ce8f6cae2b4cb9a16073 100644
--- a/components/arc/metrics/arc_metrics_service.cc
+++ b/components/arc/metrics/arc_metrics_service.cc
@@ -7,6 +7,7 @@
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
+#include "components/arc/metrics/arc_low_memory_killer_monitor.h"
 
 namespace {
 
@@ -19,8 +20,11 @@ const char kGmsProcessNamePrefix[] = "com.google.android.gms";
 namespace arc {
 
 ArcMetricsService::ArcMetricsService(ArcBridgeService* bridge_service)
-    : ArcService(bridge_service), weak_ptr_factory_(this) {
+    : ArcService(bridge_service),
+      low_memory_killer_minotor_(new ArcLowMemoryKillerMonitor()),
+      weak_ptr_factory_(this) {
   arc_bridge_service()->AddObserver(this);
+  low_memory_killer_minotor_->Start();
 }
 
 ArcMetricsService::~ArcMetricsService() {