Does Mir have to pretend to be SurfaceFlinger?

[Christopher James Halse Rogers]

Thinking about this further, I think we'll *have* to implement a shim 
libEGL in the not-too-distant future. We can't propose or use 
EGL_KHR_platform_mir unless we implement it on the Android stack. (And 
we want to, because it's useful in certain cases).

So I therefore think we *should*:
#define EGLNativeWindowType MirRenderSurface*
#define EGLNativeDisplayType MirConnection*

implement our libEGL shim providing the Mir platform on Android, and 
deprecate mir_connection_get_egl_native_display() and not implement 
mir_render_surface_get_egl_native_surface().