Prevent ProcessProxy from passing bad fds to ProcessOutputWatcher

chromeos/process_proxy/process_output_watcher.h

Index: chromeos/process_proxy/process_output_watcher.h
diff --git a/chromeos/process_proxy/process_output_watcher.h b/chromeos/process_proxy/process_output_watcher.h
index 598fd5fa1e3c72a0f96b2cbe4cdbbc2b32c66041..eb0d046c4f46c16f48b151add8651f27e8af581b 100644
--- a/chromeos/process_proxy/process_output_watcher.h
+++ b/chromeos/process_proxy/process_output_watcher.h
@@ -28,6 +28,9 @@ typedef base::Callback<void(ProcessOutputType, const std::string&)>
 // underlying thread block. It deletes itself when watching is stopped.
 class CHROMEOS_EXPORT ProcessOutputWatcher {
  public:
+  // Verifies that fds that we got are properly set.
+  static bool VerifyFileDescriptor(int fd);
+
   ProcessOutputWatcher(int out_fd, int stop_fd,
                        const ProcessOutputCallback& callback);
 
@@ -43,9 +46,6 @@ class CHROMEOS_EXPORT ProcessOutputWatcher {
   // fds, it would be nicer if it was).
   void WatchProcessOutput();
 
-  // Verifies that fds that we got are properly set.
-  void VerifyFileDescriptor(int fd);
-
   // Reads data from fd, and when it's done, invokes callback function.
   void ReadFromFd(ProcessOutputType type, int* fd);