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

base/files/file_path_watcher_linux.cc

Index: base/files/file_path_watcher_linux.cc
diff --git a/base/files/file_path_watcher_linux.cc b/base/files/file_path_watcher_linux.cc
index 6dc4ab9cd55bb8db4765bf1b21db5d32d6b91773..c9be4bacdde0493e3556fbabbcf8ebb8b28a4f08 100644
--- a/base/files/file_path_watcher_linux.cc
+++ b/base/files/file_path_watcher_linux.cc
@@ -158,6 +158,11 @@ class InotifyReaderTask : public Task {
       : 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() {