In Chromium, range.endContainer can be a non-text node type

In Chromium, range.endContainer can be a non-text type of node, which then cause EFatMarker.normalizeOffset() to fail and return -1 as the normalized offset. Result: what should be a valid selection is not highlighted.

At first glance, solution seems to be that whenever a non-text type of node is encountered for range.endContainer, to walk backward in the DOM hierarchy until a text node is found (aka finding the nearest preceding text node), at which point this text node would replace range.endContainer, and the text length of this text node would replace range.endOffset.