Parameterize and rename both `Layout::content_box_query` and
`Layout::content_boxes_query` to support the query of rendered padding
area and content area that accounts for transform and scroll. Both of
these query have been misleading for a time since they are using border
box, instead of content box of a Node.
This PR adds a new type `layout_api::BoxAreaType` to be passed from
`ScriptThread` to `LayoutThread` to query the respective area. It is
then used for the query within `IntersectionObserver` to pass several
WPTs.
Testing: Existing WPT Coverage.
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Signed-off-by: Jo Steven Novaryo <jo.steven.novaryo@huawei.com>