We want to merge all the branding work into the MobileFrontend master branch but we want to feature flag switching from a search input to a search icon.
[x] Ensure T157987 has been merged (search bar is feature flagged)
 Merge contents of branding branch onto master and confirm search button on mobile is disabled by default in stable but shown on beta.
 Ensure browser tests pass on the beta cluster
[x] Create a new task when the switchover has been merged as a reminder to remove css for cached HTML (this is captured as https://phabricator.wikimedia.org/T158144)
* No need to SWAT - just let it ride the train.