The abort here is a red herring and is masking the primary issue, which you can see a few frames further down:

#5  0x00007f87c8e3d088 in __run_exit_handlers (status=status@entry=1, listp=0x7f87c91c75f8 <__exit_funcs>, run_list_atexit=run_list_atexit@entry=true) at exit.c:82
        atfct = <optimized out>
        onfct = <optimized out>
        cxafct = <optimized out>
#6  0x00007f87c8e3d0d5 in __GI_exit (status=status@entry=1) at exit.c:104
No locals.
#7  0x00007f87bd0d2ea1 in gdk_x_io_error (display=<optimized out>) at /build/gtk+2.0-KsZKkB/gtk+2.0-2.24.30/gdk/x11/gdkmain-x11.c:544
No locals.
#8  0x00007f87c8387cee in _XIOError (dpy=dpy@entry=0x5646ce4eb0f0) at ../../src/XlibInt.c:1464
No locals.
#9  0x00007f87c8385d4a in _XReply (dpy=dpy@entry=0x5646ce4eb0f0, rep=rep@entry=0x7ffebcbf6160, extra=extra@entry=0, discard=discard@entry=1) at ../../src/xcb_io.c:708
        error = 0x0
        c = <optimized out>
        reply = 0x0
        current = 0x5646cf5f8b60
        __PRETTY_FUNCTION__ = "_XReply"
#10 0x00007f87c838148d in XSync (dpy=0x5646ce4eb0f0, discard=0) at ../../src/Sync.c:44
        rep = {type = 167 '\247', revertTo = 98 'b', sequenceNumber = 48319, length = 28, focus = 3465286592, pad1 = 0, pad2 = 3166658864, pad3 = 32766, pad4 = 32, pad5 = 0}
#11 0x00007f87c764deda in dri2SwapBuffers () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/mesa/libGL.so.1
No symbol table info available.
#12 0x00007f87cb956342 in QGLXContext::swapBuffers(QPlatformSurface*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so
No symbol table info available.
#13 0x00007f87ca495326 in QOpenGLContext::swapBuffers(QSurface*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
No symbol table info available.
#14 0x00007f87cae4978e in QSGGuiThreadRenderLoop::renderWindow(QQuickWindow*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
No symbol table info available.
#15 0x00007f87cae4a521 in QSGGuiThreadRenderLoop::event(QEvent*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
No symbol table info available.
#16 0x00007f87cb20e05c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
No symbol table info available.
#17 0x00007f87cb213516 in QApplication::notify(QObject*, QEvent*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
No symbol table info available.
#18 0x00007f87c9cf45bb in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#19 0x00007f87c9d4986d in QTimerInfoList::activateTimers() () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#20 0x00007f87c9d49d71 in timerSourceDispatch(_GSource*, int (*)(void*), void*) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#21 0x00007f87c86cc127 in g_main_context_dispatch () from /tmp/apport_sandbox_hx8GUx/lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#22 0x00007f87c86cc380 in g_main_context_iterate.isra () from /tmp/apport_sandbox_hx8GUx/lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#23 0x00007f87c86cc42c in g_main_context_iteration () from /tmp/apport_sandbox_hx8GUx/lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#24 0x00007f87c9d4aa4f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#25 0x00007f87c9cf1d7a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#26 0x00007f87c9cf9e1c in QCoreApplication::exec() () from /tmp/apport_sandbox_hx8GUx/usr/lib/x86_64-linux-gnu/libQt5Core.so.5
No symbol table info available.
#27 0x00005646ccf87e26 in BrowserApplication::run (this=0x7ffebcbf6930) at /build/webbrowser-app-W5j7m8/webbrowser-app-0.23+16.04.20160318/src/app/browserapplication.cpp:261
No locals.
#28 0x00005646ccf7ca85 in main (argc=1, argv=0x7ffebcbf6a88) at /build/webbrowser-app-W5j7m8/webbrowser-app-0.23+16.04.20160318/src/app/webbrowser/webbrowser-app.cpp:122
        app = {<BrowserApplication> = {<QApplication> = {<No data fields>}, static staticMetaObject = {d = {superdata = 0x7f87cb710140 <QApplication::staticMetaObject>, stringdata = 0x5646ccfca9c0 <qt_meta_stringdata_BrowserApplication>, data = 0x5646ccfca960 <qt_meta_data_BrowserApplication>, static_metacall = 0x5646ccf92bf0 <BrowserApplication::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, m_arguments = {<QList<QString>> = {<QListSpecialMethods<QString>> = {<No data fields>}, {p = {static shared_null = {ref = {atomic = {_q_value = -1}}, alloc = 0, begin = 0, end = 0, array = {0x0}}, d = 0x5646ce80fbe0}, d = 0x5646ce80fbe0}}, <No data fields>}, m_engine = 0x5646ce818880, m_window = 0x5646ce8c13c0, m_component = 0x5646ce8b8570, m_webbrowserWindowProxy = 0x5646ce8b8220, m_singleton = {<QObject> = {<No data fields>}, static staticMetaObject = {d = {superdata = 0x7f87c9f34b00 <QObject::staticMetaObject>, stringdata = 0x5646ccfc9f20 <qt_meta_stringdata_SingleInstanceManager>, data = 0x5646ccfc9e60 <qt_meta_data_SingleInstanceManager>, static_metacall = 0x5646ccf92680 <SingleInstanceManager::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}, m_server = <incomplete type>}}, static staticMetaObject = {d = {superdata = 0x5646cd1e70a0 <BrowserApplication::staticMetaObject>, stringdata = 0x5646ccfc8b20 <qt_meta_stringdata_WebbrowserApp>, data = 0x5646ccfc8ae0 <qt_meta_data_WebbrowserApp>, static_metacall = 0x5646ccf86ba0 <WebbrowserApp::qt_static_metacall(QObject*, QMetaObject::Call, int, void**)>, relatedMetaObjects = 0x0, extradata = 0x0}}}