UMA: How often are different network error screens encountered during OOBE

chrome/browser/chromeos/login/error_screens_histogram_helper.h

+// Copyright 2014 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_CHROMEOS_LOGIN_ERROR_SCREENS_HISTOGRAM_HELPER_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_ERROR_SCREENS_HISTOGRAM_HELPER_H_
+
+#include "chrome/browser/chromeos/login/screens/error_screen.h"
+
+namespace chromeos {
+FORWARD_DECLARE_TEST(ErrorScreensHistogramHelperTest, TestShowHideTime);
+FORWARD_DECLARE_TEST(ErrorScreensHistogramHelperTest, TestShowHideShowHideTime);
+FORWARD_DECLARE_TEST(ErrorScreensHistogramHelperTest, TestShowShowHideTime);
+
+class ErrorScreensHistogramHelper {
+ public:
+  explicit ErrorScreensHistogramHelper(const char* screen_name);

[ygorshenin1, 2014/08/26 14:33:14]

nit: replace const char* by const std::string&.

[Roman Sorokin (ftl), 2014/09/04 13:26:47]

Done.

+  void OnScreenShow();
+  void OnErrorShow(ErrorScreen::ErrorState error);
+  void OnErrorHide();
+  ~ErrorScreensHistogramHelper();
+
+ private:
+  FRIEND_TEST_ALL_PREFIXES(ErrorScreensHistogramHelperTest, TestShowHideTime);
+  FRIEND_TEST_ALL_PREFIXES(ErrorScreensHistogramHelperTest,
+                           TestShowHideShowHideTime);
+  FRIEND_TEST_ALL_PREFIXES(ErrorScreensHistogramHelperTest,
+                           TestShowShowHideTime);
+  // functions for testing.
+  void OnErrorShowTime(ErrorScreen::ErrorState error, base::Time now);
+  void OnErrorHideTime(base::Time now);

[ygorshenin1, 2014/08/26 14:33:14]

nit: add a blank line between methods and fields.

[Roman Sorokin (ftl), 2014/09/04 13:26:47]

Done.

+  std::string screen_name_;
+  bool was_shown_;
+  ErrorScreen::ErrorState last_error_shown_;
+  base::Time error_screen_start_time;
+  base::TimeDelta time_on_error_screens;
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_ERROR_SCREENS_HISTOGRAM_HELPER_H_