Function restoreSelection

code/composition/public/app.js:6662–6692

* @restoreSelection: If any selection information was potentially lost, * restore it. This is useful when performing operations that could remove dom * nodes and place them back in, resulting in focus being lost.

(priorSelectionInformation)

 * nodes and place them back in, resulting in focus being lost.
 */
function restoreSelection(priorSelectionInformation) {
  var curFocusedElem = getActiveElement();
  var priorFocusedElem = priorSelectionInformation.focusedElem;
  var priorSelectionRange = priorSelectionInformation.selectionRange;
  if (curFocusedElem !== priorFocusedElem && isInDocument(priorFocusedElem)) {
    if (hasSelectionCapabilities(priorFocusedElem)) {
      setSelection(priorFocusedElem, priorSelectionRange);
    }

    // Focusing a node can change the scroll position, which is undesirable
    var ancestors = [];
    var ancestor = priorFocusedElem;
    while (ancestor = ancestor.parentNode) {
      if (ancestor.nodeType === ELEMENT_NODE) {
        ancestors.push({
          element: ancestor,
          left: ancestor.scrollLeft,
          top: ancestor.scrollTop
        });
      }
    }

    priorFocusedElem.focus();

    for (var i = 0; i < ancestors.length; i++) {
      var info = ancestors[i];
      info.element.scrollLeft = info.left;
      info.element.scrollTop = info.top;
    }
  }
}

/**
 * @getSelection: Gets the selection bounds of a focused textarea, input or