Linux: Correctly count the number of open file descriptors.

base/files/dir_reader_linux.h

 // 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.
 
 #ifndef BASE_FILES_DIR_READER_LINUX_H_
 #define BASE_FILES_DIR_READER_LINUX_H_
 
 #include <errno.h>
 #include <fcntl.h>
 #include <stdint.h>
@@ skipping 52 matching lines @@
       DPLOG(FATAL) << "getdents64 returned an error: " << errno;
       return false;
     }
     size_ = r;
     offset_ = 0;
     return true;
   }
 
   const char* name() const {
     if (!size_)
-      return NULL;
+      return nullptr;
 
     const linux_dirent* dirent =
         reinterpret_cast<const linux_dirent*>(&buf_[offset_]);
     return dirent->d_name;
   }
 
   int fd() const {
     return fd_;
   }
 
   static bool IsFallback() {
     return false;
   }
 
  private:
   const int fd_;
   unsigned char buf_[512];
-  size_t offset_, size_;
+  size_t offset_;
+  size_t size_;
 
   DISALLOW_COPY_AND_ASSIGN(DirReaderLinux);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_DIR_READER_LINUX_H_