Fix interactive_flex demo

sky/sdk/example/rendering/interactive_flex.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 'dart:sky';
 import 'dart:math' as math;
 
+import 'package:sky/mojo/net/image_cache.dart' as image_cache;
 import 'package:sky/painting/text_style.dart';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/object.dart';
 import 'package:sky/rendering/paragraph.dart';
 import 'package:sky/rendering/sky_binding.dart';
 
 import 'solid_color_box.dart';
 
 class Touch {
   final double x;
   final double y;
   const Touch(this.x, this.y);
 }
 
 class RenderImageGrow extends RenderImage {
   final Size _startingSize;
 
-  RenderImageGrow(String src, Size size) : _startingSize = size, super(src, size);
+  RenderImageGrow(Image image, Size size) : _startingSize = size, super(image, size);
 
   double _growth = 0.0;
   double get growth => _growth;
   void set growth(double value) {
     _growth = value;
     double newWidth = _startingSize.width == null ? null : _startingSize.width + growth;
     double newHeight = _startingSize.height == null ? null : _startingSize.height + growth;
     requestedSize = new Size(newWidth, newHeight);
   }
 }
 
 RenderImageGrow image;
 
 Map<int, Touch> touches = new Map();
 void handleEvent(event) {
   if (event is PointerEvent) {
-      if (event.type == 'pointermove')
-        image.growth = math.max(0.0, image.growth + event.x - touches[event.pointer].x);
+    if (event.type == 'pointermove')
+      image.growth = math.max(0.0, image.growth + event.x - touches[event.pointer].x);
     touches[event.pointer] = new Touch(event.x, event.y);
   }
 }
 
 void main() {
   void addFlexChildSolidColor(RenderFlex parent, Color backgroundColor, { int flex: 0 }) {
     RenderSolidColorBox child = new RenderSolidColorBox(backgroundColor);
     parent.add(child);
     child.parentData.flex = flex;
   }
 
   var row = new RenderFlex(direction: FlexDirection.horizontal);
 
   // Left cell
   addFlexChildSolidColor(row, const Color(0xFF00D2B8), flex: 1);
 
   // Resizeable image
-  image = new RenderImageGrow("https://www.dartlang.org/logos/dart-logo.png",
-                              new Size(100.0, null));
+  image = new RenderImageGrow(null, new Size(100.0, null));
+  image_cache.load("https://www.dartlang.org/logos/dart-logo.png").then((Image dartLogo) {
+    image.image = dartLogo;
+  });
+
   var padding = new RenderPadding(padding: const EdgeDims.all(10.0), child: image);
   row.add(padding);
 
   RenderFlex column = new RenderFlex(direction: FlexDirection.vertical);
 
   // Top cell
   addFlexChildSolidColor(column, const Color(0xFF55DDCA), flex: 1);
 
   // The internet is a beautiful place.  https://baconipsum.com/
   String meatyString = """Bacon ipsum dolor amet ham fatback tri-tip, prosciutto
@@ skipping 16 matching lines @@
   column.parentData.flex = 8;
 
   RenderDecoratedBox root = new RenderDecoratedBox(
     decoration: new BoxDecoration(backgroundColor: const Color(0xFFFFFFFF)),
     child: row
   );
 
   new SkyBinding(root: root);
   view.setEventCallback(handleEvent);
 }