This is partially from the discussion on
Hmmm, chrome still show the window at 64K though :/
Update: looking at the streams from https://www.google.com, I don't see much different, other than the Google server also sending this frame:
[ 0.042] recv WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=0>
>>> 983041 + 65535
which I don't see us doing. Maybe we have to send that frame explicitly as well? Maybe this is a separate issue though?