This reverts commit395dbb6782. Revert "Bug 1610528 - Remove about:logo. r=dom-core,sthompson,tschuster,smaug,geckoview-reviewers,ohall,firefox-desktop-core-reviewers ,dao" This reverts commit7a7e757271. Revert "Bug 1610528 - Add XPCShellContentUtils.registerAboutPage. r=robwu" This reverts commit2ae492c37d.