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

chrome/browser/chromeos/login/error_screens_histogram_helper.cc

+// 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.
+
+#include "chrome/browser/chromeos/login/error_screens_histogram_helper.h"
+
+#include "base/metrics/histogram.h"
+
+namespace chromeos {
+
+namespace {
+
+static const char kOobeErrorScreensCounterPrefix[] = "OOBE.NetworkErrorShown.";
+static const char kOobeTimeSpentOnErrorScreensPrefix[] =
+    "OOBE.ErrorScreensTime.";
+
+std::string ErrorToString(ErrorScreen::ErrorState error) {
+  switch (error) {
+    case ErrorScreen::ERROR_STATE_PORTAL:
+      return ".Portal";
+    case ErrorScreen::ERROR_STATE_OFFLINE:
+      return ".Offline";
+    case ErrorScreen::ERROR_STATE_PROXY:
+      return ".Proxy";
+    case ErrorScreen::ERROR_STATE_AUTH_EXT_TIMEOUT:
+      return ".AuthExtTimeout";
+    default:
+      NOTREACHED() << "Invalid ErrorState " << error;
+      return std::string();
+  }
+}
+
+void StoreErrorScreenToHistogram(const std::string& screen_name,
+                                 ErrorScreen::ErrorState error) {
+  if (error <= ErrorScreen::ERROR_STATE_UNKNOWN ||
+      error > ErrorScreen::ERROR_STATE_NONE)
+    return;
+  std::string histogram_name = kOobeErrorScreensCounterPrefix + screen_name;
+  int boundary = ErrorScreen::ERROR_STATE_NONE + 1;
+  base::HistogramBase* histogram = base::LinearHistogram::FactoryGet(

[jwd, 2014/09/10 15:58:18]

Can you add a comment saying this corresponds to the UMA_HISTOGRAM_ENUMERATION
macro.

[Roman Sorokin (ftl), 2014/09/11 15:05:32]

Done.

+      histogram_name,
+      1,
+      boundary,
+      boundary + 1,
+      base::HistogramBase::kUmaTargetedHistogramFlag);
+  histogram->Add(error);
+}
+
+static const base::TimeDelta time_min = base::TimeDelta::FromMilliseconds(10);
+static const base::TimeDelta time_max = base::TimeDelta::FromMinutes(3);
+static const int time_bucket_count = 50;
+
+void StoreTimeOnErrorScreenToHistogram(const std::string& screen_name,
+                                       ErrorScreen::ErrorState error,
+                                       const base::TimeDelta& time_delta) {
+  if (error <= ErrorScreen::ERROR_STATE_UNKNOWN ||
+      error > ErrorScreen::ERROR_STATE_NONE)
+    return;
+  std::string histogram_name =
+      kOobeTimeSpentOnErrorScreensPrefix + screen_name + ErrorToString(error);
+
+  base::HistogramBase* histogram = base::LinearHistogram::FactoryTimeGet(

[jwd, 2014/09/10 15:58:18]

Having a linear histogram seems a bit odd for recording time. An exponential is
usually preferred.

[Roman Sorokin (ftl), 2014/09/11 15:05:33]

Done.

+      histogram_name,
+      time_min,
+      time_max,
+      time_bucket_count,
+      base::HistogramBase::kUmaTargetedHistogramFlag);
+
+  histogram->AddTime(time_delta);
+}
+
+}  // namespace
+
+ErrorScreensHistogramHelper::ErrorScreensHistogramHelper(
+    const std::string& screen_name)
+    : screen_name_(screen_name),
+      was_shown_(false),
+      last_error_shown_(ErrorScreen::ERROR_STATE_NONE) {
+}
+
+void ErrorScreensHistogramHelper::OnScreenShow() {
+  was_shown_ = true;
+}
+
+void ErrorScreensHistogramHelper::OnErrorShow(ErrorScreen::ErrorState error) {
+  OnErrorShowTime(error, base::Time::Now());
+}
+
+void ErrorScreensHistogramHelper::OnErrorShowTime(ErrorScreen::ErrorState error,
+                                                  base::Time now) {
+  last_error_shown_ = error;
+  if (error_screen_start_time.is_null())
+    error_screen_start_time = now;
+  StoreErrorScreenToHistogram(screen_name_, error);
+}
+
+void ErrorScreensHistogramHelper::OnErrorHide() {
+  OnErrorHideTime(base::Time::Now());
+}
+
+void ErrorScreensHistogramHelper::OnErrorHideTime(base::Time now) {
+  DCHECK(!error_screen_start_time.is_null());
+  time_on_error_screens += now - error_screen_start_time;
+  error_screen_start_time = base::Time();
+}
+
+ErrorScreensHistogramHelper::~ErrorScreensHistogramHelper() {
+  if (was_shown_) {
+    if (last_error_shown_ == ErrorScreen::ERROR_STATE_NONE) {
+      StoreErrorScreenToHistogram(screen_name_, ErrorScreen::ERROR_STATE_NONE);
+    } else {
+      if (!error_screen_start_time.is_null()) {
+        time_on_error_screens += base::Time::Now() - error_screen_start_time;
+        error_screen_start_time = base::Time();
+      }
+      StoreTimeOnErrorScreenToHistogram(
+          screen_name_, last_error_shown_, time_on_error_screens);
+    }
+  }
+}
+
+}  // namespace chromeos