Collect UMA statistics on which chrome://flags lead to chrome restart on ChromeOS.

chrome/browser/chromeos/login/login_utils.cc

 // Copyright (c) 2012 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/login_utils.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
@@ skipping 198 matching lines @@
     LoginDisplayHost* login_host) {
   if (!UserManager::Get()->GetCurrentUserFlow()->ShouldLaunchBrowser()) {
     UserManager::Get()->GetCurrentUserFlow()->LaunchExtraSteps(profile);
     return;
   }
 
   CommandLine user_flags(CommandLine::NO_PROGRAM);
   about_flags::PrefServiceFlagsStorage flags_storage_(profile->GetPrefs());
   about_flags::ConvertFlagsToSwitches(&flags_storage_, &user_flags,
                                       about_flags::kAddSentinels);
+
+  std::set<CommandLine::StringType> command_line_difference;
+
   // Only restart if needed and if not going into managed mode.
   // Don't restart browser if it is not first profile in session.
   if (UserManager::Get()->GetLoggedInUsers().size() == 1 &&
       !UserManager::Get()->IsLoggedInAsLocallyManagedUser() &&
       !about_flags::AreSwitchesIdenticalToCurrentCommandLine(
-          user_flags, *CommandLine::ForCurrentProcess())) {
+          user_flags,
+          *CommandLine::ForCurrentProcess(),
+          &command_line_difference)) {
     CommandLine::StringVector flags;
     // argv[0] is the program name |CommandLine::NO_PROGRAM|.
     flags.assign(user_flags.argv().begin() + 1, user_flags.argv().end());
     VLOG(1) << "Restarting to apply per-session flags...";
+
+    about_flags::ReportCustomFlags("Login.CustomFlags",
+                                   command_line_difference);
+
     DBusThreadManager::Get()->GetSessionManagerClient()->SetFlagsForUser(
         UserManager::Get()->GetActiveUser()->email(), flags);
     AttemptRestart(profile);
     return;
   }
 
   if (login_host) {
     login_host->SetStatusAreaVisible(true);
     login_host->BeforeSessionStart();
   }
@@ skipping 161 matching lines @@
   CrosSettings* cros_settings = CrosSettings::Get();
   bool allow_new_user = false;
   cros_settings->GetBoolean(kAccountsPrefAllowNewUser, &allow_new_user);
   if (allow_new_user)
     return true;
   return cros_settings->FindEmailInList(
       kAccountsPrefUsers, username, wildcard_match);
 }
 
 }  // namespace chromeos