Operating system: Windows 10
Graphics card: AMD Radeon R7 450
(example: 2.80, a205293426b, blender2.8, 2018-12-03 00:27)
Mask Tool visualization doesn't appear to work anymore in 2.8
Exact steps for others to reproduce the error
Add a new object, go to Texture Paint layout and set a new Texture Slot with color.
Go to top bar OR to Tool properties and turn on Mask, and add a new mask texture using existing UV.
Set the visualization color to what you expect to see when painting with the mask tool.
In UV Image Editor, load the mask image in view to see status.
Switch to Mask tool in Texture Paint mode, and paint on the mask in the 3d view.
Switch to Work Bench, Eevee, Cycles, and try to find where to turn on the visualization, and pull out hair.
This is not a finished feature in 2.8, and might need redesign to allow it to be an overlay in viewport so that it will work consistently in Workbench, Cycles,Eevee. Up til 2.79b, we had it working with Multitexture, and it didn't work with GLSL.
Including screen captures of 2.79 working and 2.8 not.