Fix remaining analyzer warnings

Constructor tear-offs aren't supported by the analyzer yet.

examples/widgets/drag_and_drop.dart

@@ -77,11 +77,8 @@ class ExampleDragSource extends StatelessComponent {
 
   Widget build(BuildContext context) {
     double size = kDotSize;
-    DraggableConstructor<Color> constructor = new Draggable<Color>#;
-    if (heavy) {
+    if (heavy)
       size *= kHeavyMultiplier;
-      constructor = new LongPressDraggable<Color>#;
-    }
 
     Widget contents = new DefaultTextStyle(
       style: Theme.of(context).text.body1.copyWith(textAlign: TextAlign.center),
@@ -112,13 +109,23 @@ class ExampleDragSource extends StatelessComponent {
       anchor = DragAnchor.child;
     }
 
-    return constructor(
-      data: color,
-      child: contents,
-      feedback: feedback,
-      feedbackOffset: feedbackOffset,
-      dragAnchor: anchor
-    );
+    if (heavy) {
+      return new Draggable<Color>(
+        data: color,
+        child: contents,
+        feedback: feedback,
+        feedbackOffset: feedbackOffset,
+        dragAnchor: anchor
+      );
+    } else {
+      return new LongPressDraggable<Color>(
+        data: color,
+        child: contents,
+        feedback: feedback,
+        feedbackOffset: feedbackOffset,
+        dragAnchor: anchor
+      );
+    }
   }
 }
 

packages/flutter/lib/src/widgets/drag_target.dart

@@ -19,15 +19,6 @@ typedef void DragTargetAccept<T>(T data);
 typedef Widget DragTargetBuilder<T>(BuildContext context, List<T> candidateData, List<dynamic> rejectedData);
 typedef void DragStartCallback(Point position, int pointer);
 
-typedef DraggableBase<T> DraggableConstructor<T>({
-  Key key,
-  T data,
-  Widget child,
-  Widget feedback,
-  Offset feedbackOffset,
-  DragAnchor dragAnchor
-});
-
 enum DragAnchor {
   /// Display the feedback anchored at the position of the original child. If
   /// feedback is identical to the child, then this means the feedback will

packages/playfair/test/playfair_test.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:test/test.dart';
-
-import 'package:playfair/playfair.dart';
-import 'test_painting_canvas.dart';
-
-void main() {
-  test('test_chart', () {
-    ChartData data = new ChartData(
-      startX: 0.0,
-      startY: 0.0,
-      endX: 10.0,
-      endY: 1.0,
-      dataSet: [
-        const Point(0.0, 0.0),
-        const Point(2.0, 0.5),
-        const Point(5.0, 0.2),
-        const Point(10.0, 0.9),
-      ]
-    );
-
-    StringBuffer buffer = new StringBuffer();
-    PaintingCanvas canvas = new TestPaintingCanvas(
-      new PictureRecorder(),
-      const Size(100.0, 100.0),
-      buffer.write
-    );
-
-    new ChartPainter(data).paint(canvas, new Rect.fromLTRB(0.0, 0.0, 100.0, 100.0));
-
-    // TODO(jackson): Update this to the correct value once Sky packages can test
-    // See https://github.com/domokit/sky_engine/issues/580
-    expect(buffer.toString(), equals(""));
-  });
-}