Enable the VariationsService on official builds when --variations-service-url is provided.

chrome/browser/metrics/variations/variations_service.h

Index: chrome/browser/metrics/variations/variations_service.h
diff --git a/chrome/browser/metrics/variations/variations_service.h b/chrome/browser/metrics/variations/variations_service.h
index 5a363874deafeb12d1c1abf36b7811bc7c3052de..380bd8eb31be91cb5a3a12216410f6d3706d6a83 100644
--- a/chrome/browser/metrics/variations/variations_service.h
+++ b/chrome/browser/metrics/variations/variations_service.h
@@ -31,12 +31,6 @@ class VariationsService
     : public net::URLFetcherDelegate,
       public ResourceRequestAllowedNotifier::Observer {
  public:
-  VariationsService();
-
-  // This constructor exists for injecting a mock notifier. It is meant for
-  // testing only. This instance will take ownership of |notifier|.
-  explicit VariationsService(ResourceRequestAllowedNotifier* notifier);
-
   virtual ~VariationsService();
 
   // Creates field trials based on Variations Seed loaded from local prefs. If
@@ -49,17 +43,24 @@ class VariationsService
   // |CreateTrialsFromSeed|.
   void StartRepeatedVariationsSeedFetch();
 
+  // Exposed for testing.
+  void SetCreateTrialsFromSeedCalledForTesting(bool called);
+
   // Register Variations related prefs in Local State.
   static void RegisterPrefs(PrefServiceSimple* prefs);
 
-  // Exposed for testing.
-  void SetCreateTrialsFromSeedCalledForTesting(bool called);
+  // Factory method for creating a VariationsService.
+  static VariationsService* Create();
 
  protected:
   // Starts the fetching process once, where |OnURLFetchComplete| is called with
   // the response.
   virtual void DoActualFetch();
 
+  // This constructor exists for injecting a mock notifier. It is meant for
+  // testing only. This instance will take ownership of |notifier|.
+  explicit VariationsService(ResourceRequestAllowedNotifier* notifier);
+
  private:
   FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, CheckStudyChannel);
   FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, CheckStudyLocale);
@@ -75,6 +76,10 @@ class VariationsService
   FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, StoreSeed);
   FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, ValidateStudy);
 
+  // Default constructor is private. Use the |Create| factory method to create a
+  // VariationsService.
+  VariationsService();
+
   // Checks if prerequisites for fetching the Variations seed are met, and if
   // so, performs the actual fetch using |DoActualFetch|.
   void FetchVariationsSeed();