The great Blink rename changed DOMWebSocket.h to dom_web_socket.h, and similarly for the other files. WebSocket is one word that happens to have a capital letter in the middle. So the file should be called dom_websocket.h.
I should have changed build/scripts/blinkbuild/name_style_converter.py before the great rename. It would have saved a lot of trouble if I'd known this.
Comment 1 by ricea@chromium.org
, Apr 23 2018