Code review comment for lp:~mir-team/mir/touchspot-renderable

touchspot_controller.cpp:
 + nits: a lot of additional whitespace ..
 + unsure: from what interfaces it needs it feels more like belonging to scene maybe?
 + needs fixing: visualize_touches will benefit a lot from extracting the three steps inside the mutex block into separate methods, and you could remove some of the comments then
 + needs fixing: touch spot render ables should be centered around the spots

I might have missed the rationale behind it, because looking at how buffer writer is looks like an alternative buffer allocator/constructor function. Especially looking at the behavior - new buffer must match the old buffer in size...?

Nit: mgm::BufferWriter::write should throw std::invalid_argument when no shm buffer is supplied.

So this is a needs information with two small needs fixing.