Reviewed by Martin Robinson.

        [GTK] Expose the AtkValue interface for WAI-ARIA sliders
        https://bugs.webkit.org/show_bug.cgi?id=56655

        New test to check WAI-ARIA sliders required attributes.

        * platform/gtk/accessibility/aria-slider-required-attributes-expected.txt: Added.
        * platform/gtk/accessibility/aria-slider-required-attributes.html: Added.
2011-03-26  Mario Sanchez Prada  <msanchez@igalia.com>

        Reviewed by Martin Robinson.

        [GTK] Expose the AtkValue interface for WAI-ARIA sliders
        https://bugs.webkit.org/show_bug.cgi?id=56655

        Implement AtkValue interface for WAI-ARIA sliders.

        Test: platform/gtk/accessibility/aria-slider-required-attributes.html

        * accessibility/gtk/AXObjectCacheAtk.cpp:
        (WebCore::AXObjectCache::postPlatformNotification): Emit the
        'property-change::accessible-value' signal when needed.

        * accessibility/gtk/AccessibilityObjectWrapperAtk.cpp:
        (core): New, returns a core object from an AtkValue.
        (webkitAccessibleValueGetCurrentValue): New, implements AtkValue.
        (webkitAccessibleValueGetMaximumValue): Ditto.
        (webkitAccessibleValueGetMinimumValue): Ditto.
        (webkitAccessibleValueSetCurrentValue): Ditto.
        (webkitAccessibleValueGetMinimumIncrement): Ditto.
        (atkValueInterfaceInit): Ditto.
        (GetAtkInterfaceTypeFromWAIType): Add ATK_TYPE_VALUE.
        (getInterfaceMaskFromObject): Set the WAI_VALUE bit for sliders.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@82095 268f45cc-cd09-0410-ab3c-d52691b4dbfc