Delegate PersistedLogs metrics recording

components/metrics/persisted_logs.h

Index: components/metrics/persisted_logs.h
diff --git a/components/metrics/persisted_logs.h b/components/metrics/persisted_logs.h
index 479924fd0fdab8fd717d6d1ad852c3d7624a04ec..2af474bb341964162a8a684cbf834a96e2c7ceeb 100644
--- a/components/metrics/persisted_logs.h
+++ b/components/metrics/persisted_logs.h
@@ -7,6 +7,7 @@
 
 #include <stddef.h>
 
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -18,6 +19,8 @@ class PrefService;
 
 namespace metrics {
 
+class PersistedLogsMetrics;
+
 // Maintains a list of unsent logs that are written and restored from disk.
 class PersistedLogs {
  public:
@@ -49,7 +52,8 @@ class PersistedLogs {
   //
   // If the optional |max_log_size| parameter is non-zero, all logs larger than
   // that limit will be skipped when writing to disk.
-  PersistedLogs(PrefService* local_state,
+  PersistedLogs(std::unique_ptr<PersistedLogsMetrics> metrics,
+                PrefService* local_state,
                 const char* pref_name,
                 const char* outdated_pref_name,
                 size_t min_log_count,
@@ -110,6 +114,9 @@ class PersistedLogs {
   // Reads the list from the ListValue in the old Log-hash pair format.
   LogReadStatus ReadLogsFromOldFormatPrefList(const base::ListValue& list);
 
+  // An object for recording UMA metrics.
+  std::unique_ptr<PersistedLogsMetrics> metrics_;
+
   // A weak pointer to the PrefService object to read and write the preference
   // from.  Calling code should ensure this object continues to exist for the
   // lifetime of the PersistedLogs object.
@@ -134,7 +141,10 @@ class PersistedLogs {
   struct LogInfo {
     // Initializes the members based on uncompressed |log_data| and
     // |log_timestamp|.
-    void Init(const std::string& log_data, const std::string& log_timestamp);
+    // |metrics| is the parent's metrics_ object, and should not be held.
+    void Init(PersistedLogsMetrics* metrics,
+              const std::string& log_data,
+              const std::string& log_timestamp);
 
     // Compressed log data - a serialized protobuf that's been gzipped.
     std::string compressed_log_data;