[release-branch.go1.2] go.tools/playground/socket: require origin to set up socket handler

««« CL 95030044 / bda3619e7a2c
go.tools/playground/socket: require origin to set up socket handler

This prevents cross-site request forgery attacks.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/95030044
»»»

TBR=rsc
CC=golang-dev
https://golang.org/cl/97040044
1 file changed