Fix unprivileged user namespace regression

chrome/browser/ui/views/chrome_browser_main_extra_parts_views.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/views/chrome_browser_main_extra_parts_views.h"
 
+#if defined(OS_LINUX)

[Tom (Use chromium acct), 2017/02/19 19:16:06]

Move ifdef'ed includes to the bottom

[Kevin Cernekee, 2017/02/19 19:33:46]

Done.

+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+
+#include <utility>
+
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/ui/views/chrome_constrained_window_views_client.h"
 #include "chrome/browser/ui/views/chrome_views_delegate.h"
 #include "chrome/browser/ui/views/ime_driver/ime_driver_mus.h"
 #include "components/constrained_window/constrained_window_views.h"
 
 #if defined(USE_AURA)
 #include "base/run_loop.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/service_manager_connection.h"
@@ skipping 53 matching lines @@
     IMEDriver::Register();
 #endif
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   // On the Linux desktop, we want to prevent the user from logging in as root,
   // so that we don't destroy the profile. Now that we have some minimal ui
   // initialized, check to see if we're running as root and bail if we are.
   if (geteuid() != 0)
     return;
 
+  // Allow running inside an unprivileged user namespace. In that case, /

[Tom (Use chromium acct), 2017/02/19 19:16:06]

remove / ?

[Kevin Cernekee, 2017/02/19 19:33:46]

I changed it to "the root directory" to make the comment easier to follow.

+  // will be owned by an unmapped UID and GID.
+  struct stat st;
+  if (stat("/", &st) == 0 && st.st_uid != 0)
+    return;
+
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kNoSandbox))
     return;
 
   base::string16 title = l10n_util::GetStringFUTF16(
       IDS_REFUSE_TO_RUN_AS_ROOT, l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
   base::string16 message = l10n_util::GetStringFUTF16(
       IDS_REFUSE_TO_RUN_AS_ROOT_2, l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
 
@@ skipping 20 matching lines @@
     // WMState is owned as a member, so don't have MusClient create it.
     const bool create_wm_state = false;
     mus_client_ = base::MakeUnique<views::MusClient>(
         connection->GetConnector(), service_manager::Identity(),
         content::BrowserThread::GetTaskRunnerForThread(
             content::BrowserThread::IO),
         create_wm_state);
   }
 #endif  // defined(USE_AURA)
 }