workaround for mac kernel bug

ipc/file_descriptor_set_posix.cc

Index: ipc/file_descriptor_set_posix.cc
diff --git a/ipc/file_descriptor_set_posix.cc b/ipc/file_descriptor_set_posix.cc
index 584efec14ae67612dba41c96ece8d14c8f1a6011..fc15c2dc5b8d5f3947c0e7cf640c2909c0aeffc5 100644
--- a/ipc/file_descriptor_set_posix.cc
+++ b/ipc/file_descriptor_set_posix.cc
@@ -126,6 +126,16 @@ void FileDescriptorSet::CommitAll() {
   consumed_descriptor_highwater_ = 0;
 }
 
+void FileDescriptorSet::ReleaseFDsToClose(std::vector<int>* fds) {
+  for (std::vector<base::FileDescriptor>::iterator
+       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
+    if (i->auto_close)
+      fds->push_back(i->fd);
+  }
+  descriptors_.clear();
+  consumed_descriptor_highwater_ = 0;
+}
+
 void FileDescriptorSet::SetDescriptors(const int* buffer, unsigned count) {
   DCHECK(count <= kMaxDescriptorsPerMessage);
   DCHECK_EQ(descriptors_.size(), 0u);