ARIA role spinbutton should expose AXRole as AXIncrementor.

ui/accessibility/platform/ax_platform_node_mac.mm

Index: ui/accessibility/platform/ax_platform_node_mac.mm
diff --git a/ui/accessibility/platform/ax_platform_node_mac.mm b/ui/accessibility/platform/ax_platform_node_mac.mm
index 03fa6b993a6c7a8e86b6c8613b1e703ad4718914..990a691729d17d32de2746241df8e74b2eabb739 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -66,7 +66,6 @@ RoleMap BuildRoleMap() {
       {ui::AX_ROLE_IMAGE, NSAccessibilityImageRole},
       {ui::AX_ROLE_IMAGE_MAP, NSAccessibilityGroupRole},
       {ui::AX_ROLE_IMAGE_MAP_LINK, NSAccessibilityLinkRole},
-      {ui::AX_ROLE_INCREMENTOR, NSAccessibilityIncrementorRole},
       {ui::AX_ROLE_LABEL_TEXT, NSAccessibilityGroupRole},
       {ui::AX_ROLE_LINK, NSAccessibilityLinkRole},
       {ui::AX_ROLE_LIST, NSAccessibilityListRole},
@@ -110,7 +109,7 @@ RoleMap BuildRoleMap() {
       {ui::AX_ROLE_SHEET, NSAccessibilitySheetRole},
       {ui::AX_ROLE_SLIDER, NSAccessibilitySliderRole},
       {ui::AX_ROLE_SLIDER_THUMB, NSAccessibilityValueIndicatorRole},
-      {ui::AX_ROLE_SPIN_BUTTON, NSAccessibilitySliderRole},
+      {ui::AX_ROLE_SPIN_BUTTON, NSAccessibilityIncrementorRole},
       {ui::AX_ROLE_SPLITTER, NSAccessibilitySplitterRole},
       {ui::AX_ROLE_SPLIT_GROUP, NSAccessibilitySplitGroupRole},
       {ui::AX_ROLE_STATIC_TEXT, NSAccessibilityStaticTextRole},