Create a field test for sync sign in promo strings.

chrome/browser/ui/webui/sync_promo_trial.h

+// Copyright (c) 2011 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_UI_WEBUI_SYNC_PROMO_TRIAL_H_
+#define CHROME_BROWSER_UI_WEBUI_SYNC_PROMO_TRIAL_H_
+
+#include "base/basictypes.h"
+
+// These helpers manage the Sync Promo field trial.
+//
+// The sync promo experiment involves changing the message body in the sign in
+// promo (see SyncPromoHandler) to see if that has any effect on sign in.
+namespace sync_promo_trial {
+  enum Group {
+    // "Get your bookmarks, history, and settings on all your devices."
+    // This is also the default message group.
+    PROMO_MSG_A = 0,
+
+    // "Back up your bookmarks, history, and settings to the web."
+    PROMO_MSG_B,
+
+    // "Sync your personalized browser features between all your devices."
+    PROMO_MSG_C,
+
+    // "You'll be automatically signed into to your favorite Google services."
+    PROMO_MSG_D,
+
+    // Bounding max value needed for UMA histogram macro.
+    PROMO_MSG_MAX,
+  };
+
+  // Activate the field trial. Before this call, all calls to GetGroup will
+  // return PROMO_MSG_A. *** MUST NOT BE CALLED MORE THAN ONCE. ***
+  void Activate();
+
+  // Returns true iff the experiment has been set up and is active. If this
+  // is false, the caller should not record stats for this experiment.
+  bool IsExperimentActive();
+
+  // Return the field trial group this client belongs to.
+  Group GetGroup();
+
+  // Return the resource ID for the Sync Promo message body associated with this
+  // client.
+  int GetMessageBodyResID();
+
+  // Record the appropriate UMA stat for when a user sees the sync promo
+  // message.
+  void RecordUserSawMessage();
+
+  // Record the appropriate UMA stat for when a user successfully signs in to
+  // GAIA.
+  void RecordUserSignedIn();
+}
+
+#endif  // CHROME_BROWSER_UI_WEBUI_SYNC_PROMO_TRIAL_H_