AX: Calling NSAccessibilityColumnsAttribute and NSAccessibilityRowsAttribute simply to get column/row count can be very expensive.
https://bugs.webkit.org/show_bug.cgi?id=124293

Reviewed by Chris Fleizach.

Source/WebCore:

Added ability to get accessibility table column or row count without fetching all columns or rows.

Test: platform/mac/accessibility/table-column-and-row-count.html

* accessibility/mac/WebAccessibilityObjectWrapperMac.mm:
(-[WebAccessibilityObjectWrapper accessibilityAttributeNames]):
(-[WebAccessibilityObjectWrapper accessibilityAttributeValue:]):

LayoutTests:

Added test to ensure NSAccessibilityColumnsAttribute and NSAccessibilityRowsAttribute
behave as expected. Also updated existing table tests to reflect this additional API.

* platform/mac/accessibility/table-column-and-row-count-expected.txt: Added.
* platform/mac/accessibility/table-column-and-row-count.html: Added.
* platform/mac/accessibility/table-detection-expected.txt:
* platform/mac/accessibility/table-with-rules-expected.txt:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159295 268f45cc-cd09-0410-ab3c-d52691b4dbfc