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

ui/accessibility/platform/ax_platform_node_auralinux.cc

Index: ui/accessibility/platform/ax_platform_node_auralinux.cc
diff --git a/ui/accessibility/platform/ax_platform_node_auralinux.cc b/ui/accessibility/platform/ax_platform_node_auralinux.cc
index f65267a9227fa968871175836f90f8f89f86bea9..47814d2e167d82bad0bfbb7c74b0f3dc657960d8 100644
--- a/ui/accessibility/platform/ax_platform_node_auralinux.cc
+++ b/ui/accessibility/platform/ax_platform_node_auralinux.cc
@@ -364,10 +364,6 @@ void ax_platform_node_auralinux_detach(
 
 G_END_DECLS
 
-//
-// AXPlatformNodeAuraLinux implementation.
-//
-
 namespace ui {
 
 // static
@@ -378,6 +374,16 @@ AXPlatformNode* AXPlatformNode::Create(AXPlatformNodeDelegate* delegate) {
 }
 
 // static
+AX_EXPORT AXPlatformNode* AXPlatformNode::FromNativeViewAccessible(
+    gfx::NativeViewAccessible accessible) {
+  return AtkObjectToAXPlatformNodeAuraLinux(accessible);
+}
+
+//
+// AXPlatformNodeAuraLinux implementation.
+//
+
+// static
 AXPlatformNode* AXPlatformNodeAuraLinux::application_ = nullptr;
 
 // static