merge fx-team to mozilla-central a=merge

.eslintignore

browser/.eslintrc

browser/app/profile/firefox.js

browser/base/content/aboutTabCrashed.js

browser/base/content/browser-gestureSupport.js

browser/base/content/browser-menubar.inc

browser/base/content/browser-sets.inc

browser/base/content/browser-syncui.js

browser/base/content/browser-trackingprotection.js

browser/base/content/browser.css

browser/base/content/browser.js

browser/base/content/browser.xul

browser/base/content/global-scripts.inc

browser/base/content/pageinfo/permissions.js

browser/base/content/sanitize.js

browser/base/content/test/general/browser.ini

browser/base/content/test/general/browser_aboutHome.js

browser/base/content/test/general/browser_syncui.js

...ase/content/test/general/browser_urlbarSearchTelemetry.js

browser/base/content/test/general/head.js