a11y: Exclude children of nested keyboard accessible controls from a11y tree.

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 3cf4db2cbf039007eeb6202e62489804c1fe57ac..bc44d953584c57a875ea312a81cd32ab89b7f4ed 100644
--- a/ui/accessibility/platform/ax_platform_node_mac.mm
+++ b/ui/accessibility/platform/ax_platform_node_mac.mm
@@ -281,6 +281,10 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
   return nil;
 }
 
+- (ui::AXPlatformNodeBase*)getNode {
+  return node_;
+}
+
 // NSAccessibility informal protocol implementation.
 
 - (BOOL)accessibilityIsIgnored {
@@ -290,7 +294,8 @@ void NotifyMacEvent(AXPlatformNodeCocoa* target, ui::AXEvent event_type) {
 
 - (id)accessibilityHitTest:(NSPoint)point {
   for (AXPlatformNodeCocoa* child in [self AXChildren]) {
-    if (NSPointInRect(point, child.boundsInScreen))
+    if (![child accessibilityIsIgnored] &&
+        NSPointInRect(point, [child boundsInScreen]))
       return [child accessibilityHitTest:point];
   }
   return NSAccessibilityUnignoredAncestor(self);
@@ -618,6 +623,14 @@ AXPlatformNode* AXPlatformNode::Create(AXPlatformNodeDelegate* delegate) {
   return node;
 }
 
+// static
+AX_EXPORT AXPlatformNode* AXPlatformNode::FromNativeViewAccessible(
+    gfx::NativeViewAccessible accessible) {
+  if ([accessible isKindOfClass:[AXPlatformNodeCocoa class]])
+    return [accessible getNode];
+  return nullptr;
+}
+
 AXPlatformNodeMac::AXPlatformNodeMac() {
 }