Add Sky framework support for drawing images

sky/examples/raw/spinning_image.dart

Index: sky/examples/raw/spinning_image.dart
diff --git a/sky/examples/raw/spinning_square.dart b/sky/examples/raw/spinning_image.dart
similarity index 66%
copy from sky/examples/raw/spinning_square.dart
copy to sky/examples/raw/spinning_image.dart
index 17072330d56a229ea035b708aba5d86df568c8ef..53fe140460f3b4dbc19e556d937e50c582b77596 100644
--- a/sky/examples/raw/spinning_square.dart
+++ b/sky/examples/raw/spinning_image.dart
@@ -6,20 +6,24 @@ import 'dart:sky';
 
 double timeBase = null;
 
+Image image;
+
 void beginFrame(double timeStamp) {
-  if (timeBase == null)
-    timeBase = timeStamp;
+  if (timeBase == null) timeBase = timeStamp;
   double delta = timeStamp - timeBase;
   PictureRecorder canvas = new PictureRecorder(view.width, view.height);
   canvas.translate(view.width / 2.0, view.height / 2.0);
   canvas.rotateDegrees(delta / 10);
-  canvas.drawRect(new Rect.fromLTRB(-100.0, -100.0, 100.0, 100.0),
-                  new Paint()..setARGB(255, 0, 255, 0));
+  canvas.scale(0.2, 0.2);
+  Paint paint = new Paint()..setARGB(255, 0, 255, 0);
+  canvas.drawImage(image, -image.width / 2.0, -image.height / 2.0, paint);
   view.picture = canvas.endRecording();
   view.scheduleFrame();
 }
 
 void main() {
+  image = new Image();
+  image.src = "https://www.dartlang.org/logos/dart-logo.png";
   view.setBeginFrameCallback(beginFrame);
   view.scheduleFrame();
 }