Enable VariationsService on Android.

BUG=224018, 168224
TEST=On a Chrome for Android official build, launch Chrome, quit it and launch it again. Go to chrome://version and verify that the string "5a3c10b5" appears in the Variations list. (This corresponds to the server-controlled Test0PercentDefault field trial).
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/13954011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195407 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 37fdcef..cdf88ca 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -204,6 +204,7 @@
   SSLConfigServiceManager::RegisterPrefs(registry);
   UpgradeDetector::RegisterPrefs(registry);
   WebCacheManager::RegisterPrefs(registry);
+  chrome_variations::VariationsService::RegisterPrefs(registry);
 
 #if defined(ENABLE_PLUGINS)
   PluginFinder::RegisterPrefs(registry);
@@ -233,7 +234,6 @@
 
 #if !defined(OS_ANDROID)
   BackgroundModeManager::RegisterPrefs(registry);
-  chrome_variations::VariationsService::RegisterPrefs(registry);
   RegisterBrowserPrefs(registry);
   RegisterDefaultBrowserPromptPrefs(registry);
   ManagedMode::RegisterPrefs(registry);