Comment 2 for bug 1045187

StacktraceTop:
 unity::dash::previews::CoverArt::OnFrameTimeout() () from /tmp/tmpuZcXJQ/usr/lib/compiz/libunityshell.so
 operator() (this=<optimized out>) at /usr/include/c++/4.6/functional:2161
 unity::glib::Source::SourceCallback (data=<optimized out>, data@entry=<error reading variable: value has been optimized out>) at /build/buildd/unity-6.4.0/UnityCore/GLibSource.cpp:106
 g_timeout_dispatch (source=0x3bb4410, source@entry=0x2498ed0, callback=<optimized out>, user_data=<optimized out>) at /build/buildd/glib2.0-2.33.10/./glib/gmain.c:4018
 g_main_dispatch (context=0x6f2da0) at /build/buildd/glib2.0-2.33.10/./glib/gmain.c:2707