Remove registerElement from app/assets/javascripts/behaviors/gl_emoji.js
Chrome 71 displays the following message in the console:
[Deprecation] document.registerElement is deprecated and will be removed in M73, around March 2019. Please use window.customElements.define instead. See https://www.chromestatus.com/features/4642138092470272 for more details.
We should replace https://gitlab.com/gitlab-org/gitlab-ce/blob/cb0f024cd4c4aa51c7824e4e1a6c4d0f307afad1/app/assets/javascripts/behaviors/gl_emoji.js#L48. Otherwise emojis will break in Chrome.