The LexicalPath instance methods dirname(), basename(), title() and
extension() will be changed to return StringView const& in a further
commit. Due to this, users creating temporary LexicalPath objects just
to call one of those getters will recieve a StringView const& pointing
to a possible freed buffer.
To avoid this, static methods for those APIs have been added, which will
return a String by value to avoid those problems. All cases where
temporary LexicalPath objects have been used as described above haven
been changed to use the static APIs.
The architecture here is a little bit convoluted. I ended up making a
new container widget (TimelineContainer) that works similarly to
GUI::ScrollableContainerWidget but has two subwidgets (a fixed header
that only scrolls vertically, and the timeline view that scrolls on
both axes.)
It would be nice to generalize this mechanism eventually and move it
back into LibGUI, but for now let's go with a special widget for
Profiler so we can continue iterating on the GUI. :^)
