Apparently I didn't so much _move_ the files as _delete_ the files. Let's re-add them.

sky/sdk/lib/editing/input.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 '../widgets/basic.dart';
+import 'editable_string.dart';
+import 'editable_text.dart';
+import 'keyboard.dart';
+
+typedef void ValueChanged(value);
+
+class Input extends Component {
+
+  Input({String key,
+         this.placeholder,
+         this.onChanged,
+         this.focused})
+      : super(key: key, stateful: true) {
+    _editableValue = new EditableString(
+      text: _value,
+      onUpdated: _handleTextUpdated
+    );
+  }
+
+  // static final Style _style = new Style('''
+  //   transform: translateX(0);
+  //   margin: 8px;
+  //   padding: 8px;
+  //   border-bottom: 1px solid ${Grey[200]};
+  //   align-self: center;
+  //   height: 1.2em;
+  //   white-space: pre;
+  //   overflow: hidden;'''
+  // );
+
+  // static final Style _placeholderStyle = new Style('''
+  //   top: 8px;
+  //   left: 8px;
+  //   position: absolute;
+  //   ${typography.black.caption};'''
+  // );
+
+  // static final String _focusedInlineStyle = '''
+  //   padding: 7px;
+  //   border-bottom: 2px solid ${Blue[500]};''';
+
+  String placeholder;
+  ValueChanged onChanged;
+  bool focused = false;
+
+  void syncFields(Input source) {
+    placeholder = source.placeholder;
+    onChanged = source.onChanged;
+    focused = source.focused;
+  }
+
+  String _value = '';
+  bool _isAttachedToKeyboard = false;
+  EditableString _editableValue;
+
+  void _handleTextUpdated() {
+    scheduleBuild();
+    if (_value != _editableValue.text) {
+      _value = _editableValue.text;
+      if (onChanged != null)
+        onChanged(_value);
+    }
+  }
+
+  Widget build() {
+    if (focused && !_isAttachedToKeyboard) {
+      keyboard.show(_editableValue.stub);
+      _isAttachedToKeyboard = true;
+    }
+
+    List<Widget> children = [];
+
+    if (placeholder != null && _value.isEmpty) {
+      children.add(new Container(
+          // style: _placeholderStyle,
+          child: new Text(placeholder)
+      ));
+    }
+
+    children.add(new EditableText(value: _editableValue, focused: focused));
+
+    return new Listener(
+      // style: _style,
+      // inlineStyle: focused ? _focusedInlineStyle : null,
+      child: new Stack(children),
+      onPointerDown: (_) => keyboard.showByRequest()
+    );
+  }
+
+  void didUnmount() {
+    if (_isAttachedToKeyboard)
+      keyboard.hide();
+    super.didUnmount();
+  }
+
+}