Split the toolbar into two modes depending on if the surface is focused:
* When unfocused, show a hamburger containing back and source switch
* When focused, show editing tools, and a check button to unfocus
For the editing toolbar, space the tools out using table-cell layout
and hide labels below 480px.
Depends on I06813e3ff in core (surface blur method).
Bug: T93325
Change-Id: Ibf09cb29019d7a71e1e144b326710b1f6506cd0c
