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

We do this by wrapping the default ctor in a factory Create method, which handles the build-type logic.

Also, group static methods in variations_service.*.
Also, move the testing constructor to protected where it's better... protected.

BUG=162417
TEST=With an unofficial build: Ensure that running Chromium without a command line argument does not result in a request to the Variations server (https://clients4.google.com/chrome-variations/seed). Ensure that providing the --variations-server-url flag with a URL results in a request to that URL.

Review URL: https://chromiumcodereview.appspot.com/11753014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175352 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/browser_process_impl.cc

@@ -416,10 +416,8 @@ net::URLRequestContextGetter* BrowserProcessImpl::system_request_context() {
 
 chrome_variations::VariationsService* BrowserProcessImpl::variations_service() {
   DCHECK(CalledOnValidThread());
-#if defined(GOOGLE_CHROME_BUILD) && !defined(OS_ANDROID)
   if (!variations_service_.get())
-    variations_service_.reset(new chrome_variations::VariationsService());
-#endif
+    variations_service_.reset(chrome_variations::VariationsService::Create());
   return variations_service_.get();
 }
 

chrome/browser/metrics/variations/variations_service.cc

@@ -159,6 +159,10 @@ void VariationsService::StartRepeatedVariationsSeedFetch() {
                this, &VariationsService::FetchVariationsSeed);
 }
 
+void VariationsService::SetCreateTrialsFromSeedCalledForTesting(bool called) {
+  create_trials_from_seed_called_ = called;
+}
+
 // static
 void VariationsService::RegisterPrefs(PrefServiceSimple* prefs) {
   prefs->RegisterStringPref(prefs::kVariationsSeed, std::string());
@@ -166,8 +170,17 @@ void VariationsService::RegisterPrefs(PrefServiceSimple* prefs) {
                            base::Time().ToInternalValue());
 }
 
-void VariationsService::SetCreateTrialsFromSeedCalledForTesting(bool called) {
-  create_trials_from_seed_called_ = called;
+// static
+VariationsService* VariationsService::Create() {
+// This is temporarily disabled for Android. See http://crbug.com/168224
+#if !defined(GOOGLE_CHROME_BUILD) || defined(OS_ANDROID)
+  // Unless the URL was provided, unsupported builds should return NULL to
+  // indicate that the service should not be used.
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kVariationsServerURL))
+    return NULL;
+#endif
+  return new VariationsService;
 }
 
 void VariationsService::DoActualFetch() {

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();

chrome/common/chrome_switches.cc

@@ -1334,7 +1334,8 @@ const char kUserDataDir[]                   = "user-data-dir";
 const char kUseWebBasedSigninFlow[]         = "use-web-based-signin-flow";
 
 // Specifies a custom URL for the server which reports variation data to the
-// client. See variations_service.cc.
+// client. Specifying this switch enables the Variations service on
+// unofficial builds. See variations_service.cc.
 const char kVariationsServerURL[]            = "variations-server-url";
 
 // Prints version information and quits.