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

ui/accessibility/platform/ax_platform_node.cc

Index: ui/accessibility/platform/ax_platform_node.cc
diff --git a/ui/accessibility/platform/ax_platform_node.cc b/ui/accessibility/platform/ax_platform_node.cc
index adfcc1e2ad2f2059b4f9d299242e7378e19fcc0c..58de0e32277e31e138569e3422b1b1d042c9e322 100644
--- a/ui/accessibility/platform/ax_platform_node.cc
+++ b/ui/accessibility/platform/ax_platform_node.cc
@@ -26,9 +26,7 @@ base::LazyInstance<UniqueIdMap> g_unique_id_map =
 AXPlatformNode* AXPlatformNode::Create(AXPlatformNodeDelegate* delegate) {
   return nullptr;
 }
-#endif  // !defined(PLATFORM_HAS_AX_PLATFORM_NODE_IMPL)
 
-#if !defined(OS_WIN)
 // This is the default implementation for platforms where native views
 // accessibility is unsupported or unfinished.
 //
@@ -37,7 +35,7 @@ AXPlatformNode* AXPlatformNode::FromNativeViewAccessible(
     gfx::NativeViewAccessible accessible) {
   return nullptr;
 }
-#endif
+#endif  // !defined(PLATFORM_HAS_AX_PLATFORM_NODE_IMPL)
 
 // static
 int32_t AXPlatformNode::GetNextUniqueId() {