base: Use std::move() instead of Pass() for real movable types.

base/metrics/histogram_base.cc

Index: base/metrics/histogram_base.cc
diff --git a/base/metrics/histogram_base.cc b/base/metrics/histogram_base.cc
index 92da79f165f465da0fd2a98041fe1bea6f933896..e9d489885f8f0dde448d278d48bd90b30881308f 100644
--- a/base/metrics/histogram_base.cc
+++ b/base/metrics/histogram_base.cc
@@ -5,6 +5,7 @@
 #include "base/metrics/histogram_base.h"
 
 #include <climits>
+#include <utility>
 
 #include "base/json/json_string_value_serializer.h"
 #include "base/logging.h"
@@ -114,8 +115,8 @@ void HistogramBase::WriteJSON(std::string* output) const {
   root.SetInteger("count", count);
   root.SetDouble("sum", static_cast<double>(sum));
   root.SetInteger("flags", flags());
-  root.Set("params", parameters.Pass());
-  root.Set("buckets", buckets.Pass());
+  root.Set("params", std::move(parameters));
+  root.Set("buckets", std::move(buckets));
   root.SetInteger("pid", GetCurrentProcId());
   serializer.Serialize(root);
 }