Running DumpRenderTree on GTK port

1. Gets source code and etc from remote repository.

- svn checkout http://svn.webkit.org/repository/webkit/trunk WebKit

For details, see http://www.webkit.org/building/checkout.html

2. Builds WebKit GTK+

- $ Tools/Scripts/build-webkit --gtk

See http://trac.webkit.org/wiki/BuildingGtk

3. Runs test

- $ Tools/Scripts/run-webkit-tests --gtk