MacViews: Gets a webview working in views_examples_with_content_exe

ui/views/widget/native_widget_mac.mm

Index: ui/views/widget/native_widget_mac.mm
diff --git a/ui/views/widget/native_widget_mac.mm b/ui/views/widget/native_widget_mac.mm
index f40c2f476281fbcb4ba69d29ecb56291ff407a46..1b4d04a09ff3c1406eadbb8b5bd18edae701dc50 100644
--- a/ui/views/widget/native_widget_mac.mm
+++ b/ui/views/widget/native_widget_mac.mm
@@ -587,7 +587,34 @@ void NativeWidgetPrivate::GetAllOwnedWidgets(gfx::NativeView native_view,
 // static
 void NativeWidgetPrivate::ReparentNativeView(gfx::NativeView native_view,
                                              gfx::NativeView new_parent) {
-  NOTIMPLEMENTED();
+  DCHECK_NE(native_view, new_parent);
+
+  gfx::NativeView old_parent = [native_view superview];
+  if (old_parent == new_parent)
+    return;
+
+  // On Mac, changing the native view heirarchy will affect at most two Widgets.
+  NativeWidgetPrivate* old_parent_widget =
+      GetNativeWidgetForNativeView(native_view);
+  NativeWidgetPrivate* new_parent_widget =
+      GetNativeWidgetForNativeView(new_parent);
+
+  if (old_parent_widget == new_parent_widget)
+    old_parent_widget = NULL;
+  if (old_parent_widget)
+    old_parent_widget->GetWidget()->NotifyNativeViewHierarchyWillChange();
+  if (new_parent_widget)
+    new_parent_widget->GetWidget()->NotifyNativeViewHierarchyWillChange();
+
+  [native_view removeFromSuperview];
+
+  if (new_parent)
+    [new_parent addSubview:native_view];
+
+  if (old_parent_widget)
+    old_parent_widget->GetWidget()->NotifyNativeViewHierarchyChanged();
+  if (new_parent_widget)
+    new_parent_widget->GetWidget()->NotifyNativeViewHierarchyChanged();
 }
 
 // static