SDL 2.x recently accepted patches to enable OpenGL ES 2 support via Google's ANGLE library. The thought is to try to eventually merge SDL/WinRT's OpenGL code with SDL-official's.
If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.
Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.