code: function () {
              if (!this.collapsed) {
                  while (!domUtils.isBody(this.startContainer) &&
                      this.startOffset == this.startContainer[this.startContainer.nodeType == 3 ? 'nodeValue' : 'childNodes'].length &&
                      this.startContainer[this.startContainer.nodeType == 3 ? 'nodeValue' : 'childNodes'].length
                      ) {
  
                      this.setStartAfter(this.startContainer);
                  }
                  while (!domUtils.isBody(this.endContainer) && !this.endOffset &&
                      this.endContainer[this.endContainer.nodeType == 3 ? 'nodeValue' : 'childNodes'].length
                      ) {
                      this.setEndBefore(this.endContainer);
                  }
              }
              return this;
          }
docs: 调整Range的边界，使其"缩小"到最合适的位置
  @method adjustmentBoundary
  @return { UE.dom.Range } 当前range对象
  @see UE.dom.Range:shrinkBoundary()