public XMLViewerImpl() {
   editor.startEditor();
   editor.setMode(AceEditorMode.XML);
   editor.setTheme(AceEditorTheme.CHROME);
   editor.setReadOnly(true);
   initWidget(editor);
 }
 @Override
 public void onResize() {
   int height = getParent().getOffsetHeight();
   int width = getParent().getOffsetWidth();
   setPixelSize(width, height);
   editor.setHeight(height + "px");
   editor.redisplay();
 }
 public void clear() {
   editor.setText(null);
 }
 @Override
 public void setContent(String content) {
   editor.setText(content);
 }