This patch is based on Makoto Kato-san's patch.
This patch implements `mozilla::dom::StaticRange` class and creating some
static factory methods.
Then, makes `AbstractRange` has a utility method of `SetStartAndEnd()`
method of `nsRange` and `StaticRange` for sharing same logic in one place.
However, there are some additional work is required only in `nsRange`, e.g.,
`nsRange` needs to start observing mutation of the range, but `StaticRange`
does not it. Therefore, it's implemented as a template method which takes
`nsRange*` or `StaticRange*` as a parameter. Then, each `DoSetRange()`
method of them can do different things without virtual calls.
Note that `StaticRange` does not have any properties, methods nor constructor.
Therefore, we need additional API to test it.
Differential Revision: https://phabricator.services.mozilla.com/D35143
--HG--
extra : moz-landing-system : lando
This patch is based on the patch created by Makoto Kato-san.
`Range` and `StaticRange` have common base interface, `AbstractRange`.
https://dom.spec.whatwg.org/#abstractrange
This interface has simply returns `startContainer`, `endContainer`,
`startOffset`, `endOffset` and `collapsed`.
Different from the original patch's approach, this patch moves related
members in `nsRange` to `AbstractRange` since this approach avoids
virtual call cost. Additionally, this patch makes them not throw as
declared by the spec. As far as I know, the destruction cost of
`ErrorResult` may appear in profile so that we should avoid creating
the instance if we can avoid it.
Unfortunately, the instance size of `nsRange` becomes larger with this
patch. The size is changed from 176 to 184. I.e., now, `nsRange`
requires bigger chunk.
Differential Revision: https://phabricator.services.mozilla.com/D35140
--HG--
extra : moz-landing-system : lando
