[UMA] Include field trial tuples in the UMA upload.

chrome/browser/metrics/metrics_log.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file defines a set of user experience metrics data recorded by
 // the MetricsService.  This is the unit of data that is sent to the server.
 
 #ifndef CHROME_BROWSER_METRICS_METRICS_LOG_H_
 #define CHROME_BROWSER_METRICS_METRICS_LOG_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/metrics/field_trial.h"
 #include "chrome/common/metrics/metrics_log_base.h"
 
 struct AutocompleteLog;
 class PrefService;
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace webkit {
@@ skipping 38 matching lines @@
 
   // Record recent delta for critical stability metrics.  We can't wait for a
   // restart to gather these, as that delay biases our observation away from
   // users that run happily for a looooong time.  We send increments with each
   // uma log upload, just as we send histogram data.  Takes the list of
   // installed plugins as a parameter because that can't be obtained
   // synchronously from the UI thread.
   void RecordIncrementalStabilityElements(
       const std::vector<webkit::WebPluginInfo>& plugin_list);
 
+ protected:
+  // Exposed for the sake of mocking in test code.
+
+  // Returns the PrefService from which to log metrics data.
+  virtual PrefService* GetPrefService();
+
+  // Fills |field_trial_ids| with the list of initialized field trials name and
+  // group ids.
+  virtual void GetFieldTrialIds(
+    std::vector<base::FieldTrial::NameGroupId>* field_trial_ids) const;
+
  private:
   FRIEND_TEST_ALL_PREFIXES(MetricsLogTest, ChromeOSStabilityData);
 
   // Writes application stability metrics (as part of the profile log).
   // NOTE: Has the side-effect of clearing those counts.
   void WriteStabilityElement(
       const std::vector<webkit::WebPluginInfo>& plugin_list,
       PrefService* pref);
 
   // Within stability group, write plugin crash stats.
@@ skipping 24 matching lines @@
 
   // Writes metrics for the profile identified by key. This writes all
   // key/value pairs in profile_metrics.
   void WriteProfileMetrics(const std::string& key,
                            const base::DictionaryValue& profile_metrics);
 
   DISALLOW_COPY_AND_ASSIGN(MetricsLog);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_LOG_H_