DOM Standard defines that offset of Range is unsigned long. However, nsRange uses int32_t to them.
This patch makes nsRange use uint32_t instead. However, this patch does NOT allow to set over INT32_MAX as offset values since a lot of users of nsRange cannot treat the values as over INT32_MAX because a lot of internal APIs take int32_t as offsets.
For easier to search such points, this patch adds static_cast<int32_t> to uint32_t variables when they are used for int32_t arguments.
And note that nsContentUtils::ComparePoints() behaves odd. It accepts negative offset and compares such value with valid offset simply. This patch still uses int32_t offset variables in nsRange::CompareNodeToRange() even though it may be negative value if nsINode::IndexOf() returns -1 because the caller of it depends on this behavior.
MozReview-Commit-ID: 8RbOgA86JuT
