Add "VisibleOnly" key to search predicate

Add "VisibleOnly" key to search predicate
https://bugs.webkit.org/show_bug.cgi?id=115491

Patch by Greg Hughes <ghughes@apple.com> on 2013-06-04
Reviewed by Chris Fleizach.

Source/WebCore:

Added support for accessibility clients to use the search predicate to find only visible elements

* accessibility/AccessibilityObject.cpp:
(WebCore::AccessibilityObject::isAccessibilityObjectSearchMatch):
(WebCore::AccessibilityObject::isOnscreen):
(WebCore):
* accessibility/AccessibilityObject.h:
(AccessibilitySearchCriteria):
(WebCore::AccessibilitySearchCriteria::AccessibilitySearchCriteria):
(AccessibilityObject):
* accessibility/mac/WebAccessibilityObjectWrapperMac.mm:
(-[WebAccessibilityObjectWrapper accessibilityAttributeValue:forParameter:]):

Tools:

Added support for accessibility clients to use the search predicate to find only visible elements

* DumpRenderTree/AccessibilityUIElement.cpp:
(uiElementForSearchPredicateCallback):
* DumpRenderTree/AccessibilityUIElement.h:
(AccessibilityUIElement):
* DumpRenderTree/ios/AccessibilityUIElementIOS.mm:
(AccessibilityUIElement::uiElementForSearchPredicate):
* DumpRenderTree/mac/AccessibilityUIElementMac.mm:
(AccessibilityUIElement::uiElementForSearchPredicate):
* WebKitTestRunner/InjectedBundle/AccessibilityUIElement.cpp:
(WTR::AccessibilityUIElement::uiElementForSearchPredicate):
* WebKitTestRunner/InjectedBundle/AccessibilityUIElement.h:
(AccessibilityUIElement):
* WebKitTestRunner/InjectedBundle/Bindings/AccessibilityUIElement.idl:
* WebKitTestRunner/InjectedBundle/mac/AccessibilityUIElementMac.mm:
(WTR::AccessibilityUIElement::uiElementForSearchPredicate):

LayoutTests:

Added tests support for visibleOnly search predicate.

* platform/mac/accessibility/search-predicate-expected.txt:
* platform/mac/accessibility/search-predicate.html:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@151179 268f45cc-cd09-0410-ab3c-d52691b4dbfc