Make a material design Input component

sky/examples/editor/editable_string.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'package:sky/services/keyboard/keyboard.mojom.dart';
 
-typedef void StringChangedCallback(EditableString updated);
+typedef void StringUpdated();
 
 class TextRange {
   final int start;
   final int end;
 
   TextRange({this.start, this.end});
   TextRange.collapsed(int position) : start = position, end = position;
   const TextRange.empty() : start = -1, end = -1;
 
   bool get isValid => start >= 0 && end >= 0;
   bool get isCollapsed => start == end;
 }
 
 class EditableString implements KeyboardClient {
   String text;
   TextRange composing = const TextRange.empty();
   TextRange selection = const TextRange.empty();
 
-  final StringChangedCallback onChanged;
+  final StringUpdated onUpdated;
 
   KeyboardClientStub stub;
 
-  EditableString({this.text: '', this.onChanged}) {
+  EditableString({this.text: '', this.onUpdated}) {
     stub = new KeyboardClientStub.unbound()..impl = this;
   }
 
   String textBefore(TextRange range) {
     return text.substring(0, range.start);
   }
 
   String textAfter(TextRange range) {
     return text.substring(range.end);
   }
@@ skipping 37 matching lines @@
 
   void commitCorrection(CorrectionData correction) {
     // TODO(abarth): Not implemented.
   }
 
   void commitText(String text, int newCursorPosition) {
     // TODO(abarth): Why is |newCursorPosition| always 1?
     TextRange committedRange = _replaceOrAppend(composing, text);
     selection = new TextRange.collapsed(committedRange.end);
     composing = const TextRange.empty();
-    onChanged(this);
+    onUpdated();
   }
 
   void deleteSurroundingText(int beforeLength, int afterLength) {
     TextRange beforeRange = new TextRange(start: selection.start - beforeLength,
                                           end: selection.start);
     TextRange afterRange = new TextRange(start: selection.end,
                                          end: selection.end + afterLength);
     _delete(afterRange);
     _delete(beforeRange);
     selection = new TextRange(start: selection.start - beforeLength,
                               end: selection.end - beforeLength);
-    onChanged(this);
+    onUpdated();
   }
 
   void setComposingRegion(int start, int end) {
     composing = new TextRange(start: start, end: end);
-    onChanged(this);
+    onUpdated();
   }
 
   void setComposingText(String text, int newCursorPosition) {
     // TODO(abarth): Why is |newCursorPosition| always 1?
     composing = _replaceOrAppend(composing, text);
     selection = new TextRange.collapsed(composing.end);
-    onChanged(this);
+    onUpdated();
   }
 
   void setSelection(int start, int end) {
     selection = new TextRange(start: start, end: end);
-    onChanged(this);
+    onUpdated();
   }
 }