MacViews/a11y: Implement NativeViewAccessibilityMac.

ui/views/accessibility/native_view_accessibility.cc

Index: ui/views/accessibility/native_view_accessibility.cc
diff --git a/ui/views/accessibility/native_view_accessibility.cc b/ui/views/accessibility/native_view_accessibility.cc
index 1d5c11a415de6507e384cb15a305141282dbc192..409ac5a80e802e46f6db09e2a8bbbb0cbce44b65 100644
--- a/ui/views/accessibility/native_view_accessibility.cc
+++ b/ui/views/accessibility/native_view_accessibility.cc
@@ -127,12 +127,6 @@ gfx::NativeViewAccessible NativeViewAccessibility::GetParent() {
   if (view_->parent())
     return view_->parent()->GetNativeViewAccessible();
 
-  // TODO: move this to NativeViewAccessibilityMac.
-#if defined(OS_MACOSX)
-  if (view_->GetWidget())
-    return view_->GetWidget()->GetNativeView();
-#endif
-
   if (parent_widget_)
     return parent_widget_->GetRootView()->GetNativeViewAccessible();