[GTK][WTR] Move getTopLevelPath() to utilities file
https://bugs.webkit.org/show_bug.cgi?id=107541

Patch by Manuel Rego Casasnovas <rego@igalia.com> on 2013-01-28
Reviewed by Martin Robinson.

* WebKitTestRunner/GNUmakefile.am: Add new files.
* WebKitTestRunner/InjectedBundle/gtk/ActivateFontsGtk.cpp:
(WTR::getOutputDir): Uses the moved method from InjectedBundleUtilities.
* WebKitTestRunner/InjectedBundle/gtk/InjectedBundleUtilities.cpp: Added.
(WTR):
(WTR::topLevelPath): Implementation moved from ActivateFontsGtk.
* WebKitTestRunner/InjectedBundle/gtk/InjectedBundleUtilities.h: Added.
(WTR): Add new method header and documentation.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@140969 268f45cc-cd09-0410-ab3c-d52691b4dbfc