Rename Gtk2UI to BuildGtkUi
Rename Gtk2UI to BuildGtkUi

Auditors: da39a3ee5e6b4b0d3255bfef95601890afd80709@darkdh

brave/electron,brave/electron,brave/electron,brave/muon,brave/muon,brave/muon,brave/electron,brave/muon,brave/electron,brave/muon,brave/electron,brave/muon