AX: buttons of number type <input> controls are not fully accessible

AX: buttons of number type <input> controls are not fully accessible
https://bugs.webkit.org/show_bug.cgi?id=70241

Staged commit part 3. Committing the new spin button classes.

Reviewed by Darin Adler.

* CMakeLists.txt:
* GNUmakefile.list.am:
* WebCore.gypi:
* WebCore.pro:
* WebCore.vcproj/WebCore.vcproj:
* WebCore.xcodeproj/project.pbxproj:
* accessibility/AccessibilitySpinButton.cpp: Added.
(WebCore::AccessibilitySpinButton::create):
(WebCore::AccessibilitySpinButton::AccessibilitySpinButton):
(WebCore::AccessibilitySpinButton::~AccessibilitySpinButton):
(WebCore::AccessibilitySpinButton::incrementButton):
(WebCore::AccessibilitySpinButton::decrementButton):
(WebCore::AccessibilitySpinButton::elementRect):
(WebCore::AccessibilitySpinButton::addChildren):
(WebCore::AccessibilitySpinButton::step):
(WebCore::AccessibilitySpinButtonPart::AccessibilitySpinButtonPart):
(WebCore::AccessibilitySpinButtonPart::create):
(WebCore::AccessibilitySpinButtonPart::elementRect):
(WebCore::AccessibilitySpinButtonPart::press):
* accessibility/AccessibilitySpinButton.h: Added.
(WebCore::AccessibilitySpinButton::setSpinButtonElement):
(WebCore::AccessibilitySpinButton::roleValue):
(WebCore::AccessibilitySpinButton::accessibilityIsIgnored):
(WebCore::AccessibilitySpinButton::isSpinButton):
(WebCore::AccessibilitySpinButtonPart::~AccessibilitySpinButtonPart):
(WebCore::AccessibilitySpinButtonPart::isIncrementor):
(WebCore::AccessibilitySpinButtonPart::setIsIncrementor):
(WebCore::AccessibilitySpinButtonPart::roleValue):
(WebCore::AccessibilitySpinButtonPart::isSpinButtonPart):
(WebCore::AccessibilitySpinButtonPart::accessibilityIsIgnored):
(WebCore::toAccessibilitySpinButton):
(WebCore::toAccessibilitySpinButtonPart):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@97756 268f45cc-cd09-0410-ab3c-d52691b4dbfc