user32: Track the number of GL surfaces for a window rather than the pixel format.

[Ken Thomases]

On May 6, 2014, at 10:23 PM, Ken Thomases wrote:

> Leaving aside the specifics of the implementation (i.e. the WGL_WINE_surface extension), conceptually, either or both of WGL and D3D need to be able to independently tell user32 to make this change in its behavior.

Oh, and D3D's requests can be temporary.

-Ken