kiosk: UMA for launch error

chrome/browser/chromeos/app_mode/kiosk_app_launch_error.cc

 // Copyright 2013 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/app_mode/kiosk_app_launch_error.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/app_mode/kiosk_app_manager.h"
 #include "chrome/grit/generated_resources.h"
+#include "chromeos/login/auth/auth_status_consumer.h"
 #include "components/prefs/scoped_user_pref_update.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace chromeos {
 
 namespace {
 
-// Key under "kiosk" dictionary to store last launch error.
-const char kKeyLaunchError[] = "launch_error";
+// Key under "kiosk" dictionary to store the last launch error.
+constexpr char kKeyLaunchError[] = "launch_error";
+
+// Key under "kiosk" dictionary to store the last cryptohome error.
+constexpr char kKeyCryptohomeFailure[] = "cryptohome_failure";
 
 }  // namespace
 
 // static
 std::string KioskAppLaunchError::GetErrorMessage(Error error) {
   switch (error) {
     case NONE:
+    case ERROR_COUNT:
       return std::string();

[tbarzic, 2017/02/28 19:18:55]

I'd treat ERROR_COUNT as an unknown error - NOTREACHED() and return
FAILED_TO_LAUNCH message

[xiyuan, 2017/02/28 21:14:57]

Done.

 
     case HAS_PENDING_LAUNCH:
     case NOT_KIOSK_ENABLED:
     case UNABLE_TO_RETRIEVE_HASH:
     case POLICY_LOAD_FAILED:
     case ARC_AUTH_FAILED:
       return l10n_util::GetStringUTF8(IDS_KIOSK_APP_FAILED_TO_LAUNCH);
 
     case CRYPTOHOMED_NOT_RUNNING:
     case ALREADY_MOUNTED:
@@ skipping 20 matching lines @@
 
 // static
 void KioskAppLaunchError::Save(KioskAppLaunchError::Error error) {
   PrefService* local_state = g_browser_process->local_state();
   DictionaryPrefUpdate dict_update(local_state,
                                    KioskAppManager::kKioskDictionaryName);
   dict_update->SetInteger(kKeyLaunchError, error);
 }
 
 // static
+void KioskAppLaunchError::SaveCryptohomeFailure(
+    const AuthFailure& auth_failure) {
+  PrefService* local_state = g_browser_process->local_state();
+  DictionaryPrefUpdate dict_update(local_state,
+                                   KioskAppManager::kKioskDictionaryName);
+  dict_update->SetInteger(kKeyCryptohomeFailure, auth_failure.reason());
+}
+
+// static
 KioskAppLaunchError::Error KioskAppLaunchError::Get() {
   PrefService* local_state = g_browser_process->local_state();
   const base::DictionaryValue* dict =
       local_state->GetDictionary(KioskAppManager::kKioskDictionaryName);
 
   int error;
   if (dict->GetInteger(kKeyLaunchError, &error))
     return static_cast<KioskAppLaunchError::Error>(error);
 
   return KioskAppLaunchError::NONE;
 }
 
 // static
-void KioskAppLaunchError::Clear() {
+void KioskAppLaunchError::RecordMetricAndClear() {
   PrefService* local_state = g_browser_process->local_state();
   DictionaryPrefUpdate dict_update(local_state,
                                    KioskAppManager::kKioskDictionaryName);
+
+  int error;
+  if (dict_update->GetInteger(kKeyLaunchError, &error))
+    UMA_HISTOGRAM_ENUMERATION("Kiosk.Launch.Error", error, ERROR_COUNT);
   dict_update->Remove(kKeyLaunchError, NULL);
+
+  int cryptohome_failure;
+  if (dict_update->GetInteger(kKeyCryptohomeFailure, &cryptohome_failure)) {
+    UMA_HISTOGRAM_ENUMERATION("Kiosk.Launch.CryptohomeFailure",
+                              cryptohome_failure,
+                              AuthFailure::NUM_FAILURE_REASONS);
+  }
+  dict_update->Remove(kKeyCryptohomeFailure, NULL);
 }
 
 }  // namespace chromeos