The Package Explorer's content provider is not extensible the same way
as the CommonNavigator so it does not contain CElement in its tree;
instead it contains IResources (IFile, etc) and Java specific elements.
However, the file language mapping property page is set to be displayed
on selections that adapt to translation units.
So this change allows IFiles to be adapted to ITranslationUnits
therefore the property page can still be shown from the Package Explorer.
Change-Id: Ia52a62c2d8800e2a4f0404bc00e346decbacaa3b
Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
44067d9115