Implement image/URL dragging for Windows Cairo backend

[Brent Fulgham]

The DragImageCairoWin.cpp was basically a stub that didn't do anything.  The attached patch provides an implementation of the corresponding CG code in terms of the Cairo API.  This allows URL drag images to appear, as well as enabling the dragging of images.

[Brent Fulgham]

Created attachment 25942 [details]
Patch implementing Windows Cairo image drag.

[Oliver Hunt]

Comment on attachment 25942 [details]
Patch implementing Windows Cairo image drag.

Do we have a typedef that encapsulates CGContextRef and struct _cairo* ?

If we do we can remove the icky ifdefs in WebDragClient.cpp, but i think it would be much better if we could get this code to  work in terms of GraphicsContext

[Brent Fulgham]

(In reply to comment #2)
> (From update of attachment 25942 [details] [review])
> Do we have a typedef that encapsulates CGContextRef and struct _cairo* ?
> 
> If we do we can remove the icky ifdefs in WebDragClient.cpp, but i think it
> would be much better if we could get this code to  work in terms of
> GraphicsContext

There are large regions of WebKit/win that are coded in terms of CoreGraphics primitives, that are just as applicable to the Cairo back-end.

I would *love* to revise these to use GraphicsContext instead -- but will that be acceptable to the Apple side of things?

This is maybe a question for Darin... 

[Brent Fulgham]

Created attachment 25974 [details]
Use GraphicContext types, rather than CG-specific calls.

[Oliver Hunt]

Comment on attachment 25974 [details]
Use GraphicContext types, rather than CG-specific calls.

r=me

[Matt Lilek]

Committed revision 39270.