Add CHECKs for file descriptors used in select() by InotifyReaderTask

base/files/file_path_watcher_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_path_watcher.h"
 
 #include <errno.h>
 #include <string.h>
 #include <sys/inotify.h>
 #include <sys/ioctl.h>
@@ skipping 140 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(FilePathWatcherImpl);
 };
 
 class InotifyReaderTask : public Task {
  public:
   InotifyReaderTask(InotifyReader* reader, int inotify_fd, int shutdown_fd)
       : reader_(reader),
         inotify_fd_(inotify_fd),
         shutdown_fd_(shutdown_fd) {
+    // Make sure the file descriptors are good for use with select().
+    CHECK_LE(0, inotify_fd_);
+    CHECK_GT(FD_SETSIZE, inotify_fd_);
+    CHECK_LE(0, shutdown_fd_);
+    CHECK_GT(FD_SETSIZE, shutdown_fd_);
   }
 
   virtual void Run() {
     while (true) {
       fd_set rfds;
       FD_ZERO(&rfds);
       FD_SET(inotify_fd_, &rfds);
       FD_SET(shutdown_fd_, &rfds);
 
       // Wait until some inotify events are available.
@@ skipping 316 matching lines @@
 }
 
 }  // namespace
 
 FilePathWatcher::FilePathWatcher() {
   impl_ = new FilePathWatcherImpl();
 }
 
 }  // namespace files
 }  // namespace base