Added the SuppressUnsupportedOSWarning policy setting.

chrome/browser/ui/startup/startup_browser_creator.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/ui/startup/startup_browser_creator.h"
 
 #include <stddef.h>
 
 #include <algorithm>   // For max().
 #include <set>
@@ skipping 457 matching lines @@
   profile_launch_observer.Get().Clear();
 }
 
 // static
 void StartupBrowserCreator::RegisterLocalStatePrefs(
     PrefRegistrySimple* registry) {
 #if defined(OS_WIN)
   registry->RegisterStringPref(prefs::kLastWelcomedOSVersion, std::string());
   registry->RegisterBooleanPref(prefs::kWelcomePageOnOSUpgradeEnabled, true);
 #endif
+  registry->RegisterBooleanPref(prefs::kSuppressUnsupportedOSWarning, false);

[Andrew T Wilson (Slow), 2016/03/27 09:28:44]

Should this be behind a !OS_ANDROID flag?

[grt (UTC plus 2), 2016/03/27 13:03:50]

No. This cc file is in chrome_browser_ui_non_mobile_sources, so it isn't
compiled on Android or iOS. Thanks for checking.

   registry->RegisterBooleanPref(prefs::kWasRestarted, false);
 }
 
 // static
 std::vector<GURL> StartupBrowserCreator::GetURLsFromCommandLine(
     const base::CommandLine& command_line,
     const base::FilePath& cur_dir,
     Profile* profile,
     bool* show_desktop_search_redirection_infobar) {
   DCHECK(profile);
@@ skipping 384 matching lines @@
   }
 
   // If we are showing the app list then chrome isn't shown so load the app
   // list's profile rather than chrome's.
   if (command_line.HasSwitch(switches::kShowAppList))
     return AppListService::Get()->GetProfilePath(user_data_dir);
 
   return g_browser_process->profile_manager()->GetLastUsedProfileDir(
       user_data_dir);
 }