Convert FieldTrialList to Accept a std::unique_ptr

base/metrics/field_trial.h

Index: base/metrics/field_trial.h
diff --git a/base/metrics/field_trial.h b/base/metrics/field_trial.h
index 28a4606a88438d2d0c68687e24c34a14d3313fa7..2b8894904dd350e94899581bd858506300e83cd7 100644
--- a/base/metrics/field_trial.h
+++ b/base/metrics/field_trial.h
@@ -58,6 +58,7 @@
 #include <stdint.h>
 
 #include <map>
+#include <memory>
 #include <set>
 #include <string>
 #include <vector>
@@ -338,11 +339,12 @@ class BASE_EXPORT FieldTrialList {
 
   // This singleton holds the global list of registered FieldTrials.
   //
-  // To support one-time randomized field trials, specify a non-NULL
+  // To support one-time randomized field trials, specify a non-null
   // |entropy_provider| which should be a source of uniformly distributed
-  // entropy values. Takes ownership of |entropy_provider|. If one time
-  // randomization is not desired, pass in NULL for |entropy_provider|.
-  explicit FieldTrialList(const FieldTrial::EntropyProvider* entropy_provider);
+  // entropy values. If one time randomization is not desired, pass in null for
+  // |entropy_provider|.
+  explicit FieldTrialList(
+      std::unique_ptr<const FieldTrial::EntropyProvider> entropy_provider);
 
   // Destructor Release()'s references to all registered FieldTrial instances.
   ~FieldTrialList();