Blender UI paper cuts

[ArmandoTello]

This has been suggested multiple times. There was someone working on it, but has been silent for a while. Then someone else started working on it. You can look at the post here:

Gradient vertex color for proportional editing

Hi. I am new the Blender source code development. I want to add gradient vertex color feature for proportional editing mode like Maya. Currently I am tweaking the editor and bmesh codes. Could anyone help me about where I should look in order to set vertex colors in edit mode?