vcl: GtkSalFrame::AcquireGraphics() calls GtkSalGraphics::Init() twice

We really don't want to call on GtkSalGraphics::Init() twice, the only
reason we do this is because we pass in a new screen. To get around this,
I've created a new GtkSalGraphics constructor that takes and additional
screen parameter.

Change-Id: Ie53d609c2b8f64d77a3bfb2efe0e97027c75c5d0
vcl: remove obsolete commented out assert from window.cxx

Change-Id: Ibf478abae5aa0574279e8b45c26b96ab66bfe203
vcl: remove dead code from brdwin.cxx

Change-Id: I97d5a8dc85fe77c6bf0235425db0a7b9e42ff869
vcl: remove dead code and useless task comments from winproc.cxx

Change-Id: I10e4a0aa23fe83fa0f2edd671b321fa4588c880f
vcl: no such thing as GtkSalInstance, remove commented code

Change-Id: I6627363aea34570b5f7d118b1d64b6a2d93c19cb
vcl: BitmapEx now states which icon theme is being used for missing image

Change-Id: I83b9c86685f72569c0df88231458183b1ae511c8