Avoid LayoutFullScreen to be orthogonal writing-mode roots when reattached
The previous CL to avoid LayoutFullScreen to be orthogonal writing-mode
roots copied the writing-mode when adding it to the parent. However,
when reattach occurs, LayoutTreeBuilder creates LayoutFullScreen
before the target is added to the parent, and thus LayoutFullScreen
fails to copy from the parent.
This patch copies the writing-mode when creating LayoutFullScreen.