2016-06-01  Carlos Garcia Campos  <cgarcia@igalia.com>

        [Wayland] PlatformDisplayWayland destructor is super crashy

        https://bugs.webkit.org/show_bug.cgi?id=157973

        Reviewed by NOBODY (OOPS!).

        EGL registers two at exist callbacks one to finish the display and another one to unload drivers, the one to

        finish the display happens first. When our destructor is called the _eglFiniDisplay callback has already been

        called, so we have a valid pointer for an already finished display. Then eglTerminate tries to find the display

        in the global display list, but fails and for some reason it crashes when trying to return an error.

        If atexit is called after the global PlatformDisplay constructor, the atexit handler is called before the

        destructor. The atexit callbacks are called in reverse order, so if we register an atexit handler after the

        global instace has been created and after EGL has been initialized, we could terminate the EGL display before

        the EGL atexit handlers and the global PlatformDisplay destructor.

        * platform/graphics/PlatformDisplay.cpp:

        (WebCore::PlatformDisplay::initializeEGLDisplay):

    // EGL registers atexit handlers to cleanup its global display list.

    // Since the global PlatformDisplay instance is created before,

    // when the PlatformDisplay destructor is called, EGL has already removed the

    // display from the list, causing eglTerminate() to crash. So, here we register

    // our own atexit handler, after EGL has been initialized and after the global

    // instance has been created to ensure we call eglTerminate() before the other

    // EGL atexit handlers and the PlatformDisplay destructor.

    // See https://bugs.webkit.org/show_bug.cgi?id=157973.

    std::atexit([] { PlatformDisplay::sharedDisplay().terminateEGLDisplay(); });