Reviewed by Martin Robinson.

        [GTK] ATs should be able to select/unselect text
        https://bugs.webkit.org/show_bug.cgi?id=25673

        Implement AtkText's setSelection and removeSelection functions

        * accessibility/AccessibilityObject.cpp:
        (WebCore::AccessibilityObject::visiblePositionRangeForRange):
        Moved some GTK specific code from a ifdef-endif region to
        AccessibilityObjectAtk.cpp
        * accessibility/AccessibilityObject.h:
        * accessibility/gtk/AccessibilityObjectAtk.cpp:
        (WebCore::AccessibilityObject::getLengthForTextRange): New.
        * accessibility/gtk/AccessibilityObjectWrapperAtk.cpp:
        (webkit_accessible_text_remove_selection): Implemented following
        the lead of GAIL's implementation of the AtkText interface.
        (webkit_accessible_text_set_selection): Implemented following
        the lead of GAIL's implementation of the AtkText interface.
        (webkit_accessible_text_set_caret_offset): Changed to directly use
        visiblePositionRangeForRange now that there's no longer a problem
        with that, as it was in the past (only worked for text controls).
2010-09-13  Mario Sanchez Prada  <msanchez@igalia.com>

        Reviewed by Martin Robinson.

        [GTK] Provide unit tests for AtkText's text selection functions
        https://bugs.webkit.org/show_bug.cgi?id=43919

        New tests to check getting, setting and removing text selections

        * tests/testatk.c:
        (testWekitAtkTextSelections): New unit tests to check all the text
        selection related functions altogether through a single test
        function.
        (main):

        Make sure that code dependant on getting information from the
        clipboard gets executed only when there's a GDK window associated
        to the webview widget, as that's not the case when executing the
        unit tests (the wedbview is not inside of any toplevel window) and
        will make the tests crash if not taken into account.

        * WebCoreSupport/EditorClientGtk.cpp:
        (WebKit::EditorClient::respondToChangedSelection):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@67383 268f45cc-cd09-0410-ab3c-d52691b4dbfc