In AOSP qemu, the fallback software rendering EGL lib doesn't support GLES 2.0, which means the GL context isn't created by GLContextProviderEGL.
Currently, accelerated rendering and the framebuffer are only initialized before the attempt to create the GL context.
The fix is to wait until _after_ attempting to create the GL context before checking whether the framebuffer needs to be initialized, and then appropriately set the |mUseAcceleratedRendering| flag..
(Note: move this to Widget: Gonk component once it's created in Bug 771591)
The 2nd half of the emulator black screen issue on B2G github:
Created attachment 639755 [details] [diff] [review]
Framebuffer fallback on !sGLContext
Created attachment 639762 [details] [diff] [review]
Framebuffer fallback on !sGLContext - v2
Created attachment 639836 [details] [diff] [review]
Framebuffer fallback on !sGLContext - v2 (rebased)