Fix locationOf for empty hash targets in Webkit

[elliotdickison]

Internal hash links were broken in Webkit if they pointed to empty elements. This change fixes that by temporarily inserting a zero-width space into elements before measuring them.

[johnfactotum]

The function seems to contradict itself. In WebKit, in the case of a collapsed range, it tries to use an element instead of the range, but then in the case of an element, it does the exact opposite, creating a range from the element, which in the case of an empty element would result in a collapsed range.

Testing it a bit, with the latest WebKitGTK, I believe the problem is actually that a collapsed range doesn't return the correct rect. For elements, it reports the correct rect, whether the element is empty or in columns or not. So I think this can be fixed by simply removing the check all together:

diff --git a/src/contents.js b/src/contents.js
index 3effe72..63d0482 100644
--- a/src/contents.js
+++ b/src/contents.js
@@ -666,14 +666,7 @@ class Contents {
                        let id = target.substring(target.indexOf("#")+1);
                        let el = this.document.getElementById(id);
                        if(el) {
-                               if (isWebkit) {
-                                       // Webkit reports incorrect bounding rects in Columns
-                                       let newRange = new Range();
-                                       newRange.selectNode(el);
-                                       position = newRange.getBoundingClientRect();
-                               } else {
-                                       position = el.getBoundingClientRect();
-                               }
+                               position = el.getBoundingClientRect();
                        }
                }

[elliotdickison]

Ha good catch, works for me!

[elliotdickison]

@fchasen Any chance you could merge this?