Variations Service now creates field trials from variations seed.

chrome/browser/metrics/variations_service.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.
 
 #ifndef CHROME_BROWSER_METRICS_VARIATIONS_SERVICE_H_
 #define CHROME_BROWSER_METRICS_VARIATIONS_SERVICE_H_
 #pragma once
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/time.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/metrics/proto/study.pb.h"
 #include "chrome/browser/metrics/proto/trials_seed.pb.h"
 #include "chrome/common/chrome_version_info.h"
 #include "content/public/common/url_fetcher_delegate.h"
 
 template <typename T> struct DefaultSingletonTraits;
 class PrefService;
 
 // Used to setup field trials based on stored variations seed data, and fetch
 // new seed data from the variations server.
 class VariationsService : public content::URLFetcherDelegate {
  public:
   // Returns the singleton instance;
   static VariationsService* GetInstance();
 
-  // Loads the Variations seed data from the given local prefs. If there is a
-  // problem with loading, the pref value is cleared.
-  void LoadVariationsSeed(PrefService* local_prefs);
+  // Creates field trials based on Variations Seed loaded from local prefs. If
+  // there is a problem loading the seed data, all trials specified by the seed
+  // may not be created.
+  bool CreateTrialsFromSeed(PrefService* local_prefs);
 
   // Starts the fetching process, where |OnURLFetchComplete| is called with the
   // response.
   void StartFetchingVariationsSeed();
 
   // content::URLFetcherDelegate implementation:
   virtual void OnURLFetchComplete(const content::URLFetcher* source) OVERRIDE;
 
   // Register Variations related prefs in Local State.
   static void RegisterPrefs(PrefService* prefs);
@@ skipping 24 matching lines @@
                                 chrome::VersionInfo::Channel channel);
 
   // Checks whether |study| is applicable for the given version string.
   static bool CheckStudyVersion(const chrome_variations::Study& study,
                                 const std::string& version_string);
 
   // Checks whether |study| is applicable for the given date/time.
   static bool CheckStudyDate(const chrome_variations::Study& study,
                              const base::Time& date_time);
 
+  // Loads the Variations seed data from the given local prefs into |seed|. If
+  // there is a problem with loading, the pref value is cleared and false is
+  // returned. If successful, |seed| will contain the loaded data and true is
+  // returned.
+  bool LoadVariationsSeed(PrefService* local_prefs,

[Alexei Svitkine (slow), 2012/05/08 03:41:34]

Also, see my previous comment: rename this to LoadTrialsSeedFromPrefs().

[jwd, 2012/05/08 03:53:37]

Done.

+                          chrome_variations::TrialsSeed* seed);
+
+  void CreateTrialFromStudy(const chrome_variations::Study& study);
+
   // Contains the current seed request. Will only have a value while a request
   // is pending, and will be reset by |OnURLFetchComplete|.
   scoped_ptr<content::URLFetcher> pending_seed_request_;
 
   // The variations seed data being used for this session.
   // TODO(jwd): This should be removed. When the seed data is loaded, it will be
   // used immediately so it won't need to be stored.
   chrome_variations::TrialsSeed variations_seed_;
 };
 
 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_SERVICE_H_