Give the Stocks2 App a new improved toolbar.

sky/engine/core/painting/Size.dart

Index: sky/engine/core/painting/Size.dart
diff --git a/sky/engine/core/painting/Size.dart b/sky/engine/core/painting/Size.dart
index f2d43a65ca1b621bbf42bea715d00ada928bde12..2396cdd464e9407a1d63180fbb5f71028ecc05da 100644
--- a/sky/engine/core/painting/Size.dart
+++ b/sky/engine/core/painting/Size.dart
@@ -13,6 +13,9 @@ class Size {
 
   const Size.infinite() : width = double.INFINITY, height = double.INFINITY;
 
+  const Size.onlyWidth(this.width) : height = 0.0;
+  const Size.onlyHeight(this.height) : width = 0.0;

[abarth-chromium, 2015/06/02 23:09:04]

We don't want the other value to be null.  Instead, we should set it to
double.INFINITY.  For example:

const Size.onlyWidth(this.width) : height = 0.0, height = double.INFINITY;

+
   bool operator ==(other) {
     if (!(other is Size)) return false;
     return width == other.width && height == other.height;