fix text input issue caused by incorrect TextDirection

com.unity.uiwidgets/Runtime/ui2/text.cs

     }
 
     public enum TextDirection {
+        rtl,
-        rtl
     }
 
     public class TextBox : IEquatable<TextBox> {

com.unity.uiwidgets/Runtime/widgets/app.cs

             Widget result;
             if (widget.builder != null) {
                 result = new Builder(
-                    builder: context1 => { return widget.builder(context: context, child: navigator); });
+                    builder: context1 => { return widget.builder(context: context1, child: navigator); });
             }
             else {
                 D.assert(navigator != null);
 
                 return true;
             });
+            
+            //Fix Me !!
+            //TODO: the following line is a work-around for some potential TextDirection bug
+            //In the home page of the Shrine sample, the positions of the buttons are not correct, which is 
+            //determined by the TextDirection of some widget. we should fix it!
+            result = new Directionality(child: result, TextDirection.ltr);
 
             Widget title = null;
             if (widget.onGenerateTitle != null) {

com.unity.uiwidgets/Runtime/widgets/image.cs

         }
 
         void _resolveImage() {
+            //TODO: why refactoring this code? we need a PR to fix it!
             /*ScrollAwareImageProvider<object> provider = new ScrollAwareImageProvider<object>(
                 context: _scrollAwareContext,
                 imageProvider: widget.image);*/

com.unity.uiwidgets/Runtime/widgets/shortcuts.cs

             }
 
             D.assert(context != null);
-            /*LogicalKeySet keySet = keysPressed ?? new LogicalKeySet(RawKeyboard.instance.keysPressed);
+            //FIX ME !
+            //Since we process key event produced by Unity instead of raw input info (physical key)  from os directly,
+            //we cannot handle the shortcut key press as in original flutter code
+            //TODO: however, we need find out a way to make this work in another way
+            return false;
+
+            /*
+            LogicalKeySet keySet = keysPressed ?? new LogicalKeySet(RawKeyboard.instance.keysPressed);
             Intent matchedIntent = _shortcuts[keySet];
             if (matchedIntent == null) {
              
                 return false;
               }
               return Actions.invoke(primaryContext, matchedIntent, nullOk: true);
-            }*/
+            }
+            
+            */
         }
 
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {