IPC: Increase MAX_DESCRIPTORS_PER_MESSAGE

ipc/file_descriptor_set_posix.h

Index: ipc/file_descriptor_set_posix.h
diff --git a/ipc/file_descriptor_set_posix.h b/ipc/file_descriptor_set_posix.h
index d1567278815f981def972888f0fa982e71c104da..cbd24284fa6a6289eb81941a00ae3823f5f3f041 100644
--- a/ipc/file_descriptor_set_posix.h
+++ b/ipc/file_descriptor_set_posix.h
@@ -30,7 +30,7 @@ class FileDescriptorSet : public base::RefCountedThreadSafe<FileDescriptorSet> {
   // In debugging mode, it's a fatal error to try and add more than this number
   // of descriptors to a FileDescriptorSet.
   enum {
-    MAX_DESCRIPTORS_PER_MESSAGE = 4,
+    MAX_DESCRIPTORS_PER_MESSAGE = 5,
   };
 
   // ---------------------------------------------------------------------------