MetricsService: Send a hash of the UMA log in a header.

chrome/browser/metrics/metrics_log_serializer.h

Index: chrome/browser/metrics/metrics_log_serializer.h
===================================================================
--- chrome/browser/metrics/metrics_log_serializer.h	(revision 228712)
+++ chrome/browser/metrics/metrics_log_serializer.h	(working copy)
@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_
 #define CHROME_BROWSER_METRICS_METRICS_LOG_SERIALIZER_H_
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "chrome/common/metrics/metrics_log_manager.h"
@@ -38,10 +40,12 @@
   virtual ~MetricsLogSerializer();
 
   // Implementation of MetricsLogManager::LogSerializer
-  virtual void SerializeLogs(const std::vector<std::string>& logs,
-                             MetricsLogManager::LogType log_type) OVERRIDE;
-  virtual void DeserializeLogs(MetricsLogManager::LogType log_type,
-                               std::vector<std::string>* logs) OVERRIDE;
+  virtual void SerializeLogs(
+      const std::vector<MetricsLogManager::SerializedLog>& logs,
+      MetricsLogManager::LogType log_type) OVERRIDE;
+  virtual void DeserializeLogs(
+      MetricsLogManager::LogType log_type,
+      std::vector<MetricsLogManager::SerializedLog>* logs) OVERRIDE;
 
  private:
   // Encodes the textual log data from |local_list| and writes it to the given
@@ -49,16 +53,17 @@
   // with the most recent, and working backward until at least
   // |list_length_limit| logs and |byte_limit| bytes of logs have been
   // stored. At least one of those two arguments must be non-zero.
-  static void WriteLogsToPrefList(const std::vector<std::string>& local_list,
-                                  size_t list_length_limit,
-                                  size_t byte_limit,
-                                  base::ListValue* list);
+  static void WriteLogsToPrefList(
+      const std::vector<MetricsLogManager::SerializedLog>& local_list,
+      size_t list_length_limit,
+      size_t byte_limit,
+      base::ListValue* list);
 
   // Decodes and verifies the textual log data from |list|, populating
   // |local_list| and returning a status code.
   static LogReadStatus ReadLogsFromPrefList(
       const base::ListValue& list,
-      std::vector<std::string>* local_list);
+      std::vector<MetricsLogManager::SerializedLog>* local_list);
 
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, EmptyLogList);
   FRIEND_TEST_ALL_PREFIXES(MetricsLogSerializerTest, SingleElementLogList);