add support for default theme

src/Avalonia.Themes.Default/TextBox.xaml

@@ -35,14 +35,16 @@
             <DataValidationErrors>
               <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
                             VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
-
-                <Panel>
+                
+                <Grid ColumnDefinitions="Auto,*,Auto">
+                  <ContentPresenter Grid.Column="0" Grid.ColumnSpan="1" Content="{TemplateBinding InnerLeftContent}"/>
                   <TextBlock Name="watermark"
                              Opacity="0.5"
                              Text="{TemplateBinding Watermark}"
                              TextAlignment="{TemplateBinding TextAlignment}"
                              TextWrapping="{TemplateBinding TextWrapping}"
-                             IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"/>
+                             IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"
+                             Grid.Column="1" Grid.ColumnSpan="1"/>
                   <TextPresenter Name="PART_TextPresenter"
                                  Text="{TemplateBinding Text, Mode=TwoWay}"
                                  CaretIndex="{TemplateBinding CaretIndex}"
@@ -51,10 +53,13 @@
                                  TextAlignment="{TemplateBinding TextAlignment}"
                                  TextWrapping="{TemplateBinding TextWrapping}"
                                  PasswordChar="{TemplateBinding PasswordChar}"
+                                 RevealPassword="{TemplateBinding RevealPassword}"
                                  SelectionBrush="{TemplateBinding SelectionBrush}"
                                  SelectionForegroundBrush="{TemplateBinding SelectionForegroundBrush}"
-                                 CaretBrush="{TemplateBinding CaretBrush}"/>
-                </Panel>
+                                 CaretBrush="{TemplateBinding CaretBrush}"
+                                 Grid.Column="1" Grid.ColumnSpan="1"/>
+                  <ContentPresenter Grid.Column="2" Grid.ColumnSpan="1" Content="{TemplateBinding InnerRightContent}"/>
+                </Grid>
               </ScrollViewer>
             </DataValidationErrors>
           </DockPanel>