function apply() {
  chrome.storage.local.get('sites', function(result) {
    let enabledSites = result.sites;

    setScriptBlocking(enabledSites);
    setXhrBlocking(enabledSites);
    setCookieBlocking(enabledSites);
    setHeaderInjection(enabledSites);
  });
}
@param {string} name - Name of the header to be inserted
@param {string} value - Value of the header to be inserted
@param {Object[]} requestHeaders - Provided by webRequest
  listeners in callback arg `details.requestHeader`
@param {string} requestHeaders[].name
@param {string} requestHeaders[].value