[FIX] web_editor: solve all triple-click issues

... hopefully.

This *must* be forward-ported.

Depending on the browser, the triple-click behavior is different. This
is especially problematic on Chrome, where blank characters at the start
of the neighbor of the clicked element are selected.

A weak attempt to solve that was made by commit https://github.com/odoo/odoo/commit/b85bd358234684974f9af63bc5f28cfabb527767

This commit hopes to solve all the issues once and for all by fully
reimplementing the triple-click for all browsers. The concept is simple:
when a triple-click occurs, select the whole *inner* content of the
deepest DOM *element* that was clicked.

addons/web_editor/static/src/js/rte.js

@@ -583,8 +583,8 @@ var RTE = Widget.extend({
     onEnableEditableArea: function ($editable) {
     },
 
-    onMouseup: function (event) {
-        var $target = $(event.target);
+    onMouseup: function (ev) {
+        var $target = $(ev.target);
         var $editable = $target.closest('.o_editable');
 
         if (!$editable.size()) {
@@ -596,26 +596,16 @@ var RTE = Widget.extend({
             self.historyRecordUndo($target, 'activate',  true);
         },0);
 
-        // To Fix Google Chrome Tripleclick Issue, which selects the ending
-        // whitespace characters (so Tripleclicking then typing text will remove
-        // the whole paragraph instead of its content).
-        // http://stackoverflow.com/questions/38467334/why-does-google-chrome-always-add-space-after-selected-text
-        if ($.browser.chrome === true && event.originalEvent.detail === 3) {
-            var currentSelection = range.create();
-            if (currentSelection.sc.parentNode === currentSelection.ec) {
-                _selectSC(currentSelection);
-            } else if (currentSelection.eo === 0) {
-                var $hasNext = $(currentSelection.sc).parent();
-                while (!$hasNext.next().length && !$hasNext.is('body')) {
-                    $hasNext = $hasNext.parent();
-                }
-                if ($hasNext.next()[0] === currentSelection.ec) {
-                    _selectSC(currentSelection);
-                }
-            }
-        }
-        function _selectSC(selection) {
-            range.create(selection.sc, selection.so, selection.sc, selection.sc.length).select();
+        // Browsers select different content from one to another after a
+        // triple click (especially: if triple-clicking on a paragraph on
+        // Chrome, blank characters of the element following the paragraph are
+        // selected too)
+        //
+        // The triple click behavior is reimplemented for all browsers here
+        if (ev.originalEvent.detail === 3) {
+            // Select the whole content inside the deepest DOM element that was
+            // triple-clicked
+            range.create(ev.target, 0, ev.target, ev.target.childNodes.length).select();
         }
     },