libchrome: Several upstreamable fixes from libchrome

base/files/file_util_linux.cc

 // Copyright (c) 2011 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 "base/files/file_util.h"
 
 #include <errno.h>
 #include <linux/magic.h>
+#include <stdint.h>
 #include <sys/vfs.h>
 
 #include "base/files/file_path.h"
 
 namespace base {
 
 bool GetFileSystemType(const FilePath& path, FileSystemType* type) {
   struct statfs statfs_buf;
   if (statfs(path.value().c_str(), &statfs_buf) < 0) {
     if (errno == ENOENT)
       return false;
     *type = FILE_SYSTEM_UNKNOWN;
     return true;
   }
 
   // Not all possible |statfs_buf.f_type| values are in linux/magic.h.
   // Missing values are copied from the statfs man page.
-  switch (statfs_buf.f_type) {
+  // In some platforms, |statfs_buf.f_type| is declared as signed, but some of
+  // the values will overflow it, causing narrowing warnings. Cast to the
+  // largest possible unsigned integer type to avoid it.
+  switch (static_cast<uintmax_t>(statfs_buf.f_type)) {
     case 0:
       *type = FILE_SYSTEM_0;
       break;
     case EXT2_SUPER_MAGIC:  // Also ext3 and ext4
     case MSDOS_SUPER_MAGIC:
     case REISERFS_SUPER_MAGIC:
     case BTRFS_SUPER_MAGIC:
     case 0x5346544E:  // NTFS
     case 0x58465342:  // XFS
     case 0x3153464A:  // JFS
@@ skipping 17 matching lines @@
     case CGROUP_SUPER_MAGIC:
       *type = FILE_SYSTEM_CGROUP;
       break;
     default:
       *type = FILE_SYSTEM_OTHER;
   }
   return true;
 }
 
 }  // namespace base