Make EdgeDims and BoxConstraints printable (for debugging)

sky/sdk/lib/framework/rendering/box.dart

Index: sky/sdk/lib/framework/rendering/box.dart
diff --git a/sky/sdk/lib/framework/rendering/box.dart b/sky/sdk/lib/framework/rendering/box.dart
index cfa83a7cac4506c6546e6a02c09d0b6db3e455bf..f2b33fe86fe76457f15849ee758e171ce782aa57 100644
--- a/sky/sdk/lib/framework/rendering/box.dart
+++ b/sky/sdk/lib/framework/rendering/box.dart
@@ -36,6 +36,16 @@ class EdgeDims {
                                  (right == other.right) ||
                                  (bottom == other.bottom) ||
                                  (left == other.left);
+
+  int get hashCode {
+    value = 373;
+    value = 37 * value + top.hashCode;

[eseidel, 2015/06/03 23:23:16]

Why the magic number?  And doesn't dart have a *=?

+    value = 37 * value + left.hashCode;
+    value = 37 * value + bottom.hashCode;
+    value = 37 * value + right.hashCode;
+    return value;
+  }
+  String toString() => "EdgeDims($top, $right, $bottom, $left)";
 }
 
 class BoxConstraints {
@@ -87,6 +97,16 @@ class BoxConstraints {
   }
 
   bool get isInfinite => maxWidth >= double.INFINITY || maxHeight >= double.INFINITY;
+
+  int get hashCode {
+    value = 373;
+    value = 37 * value + minWidth.hashCode;

[eseidel, 2015/06/03 23:23:16]

Maybe we want a hash() helper which can take N num values and spit out a hash?

+    value = 37 * value + maxWidth.hashCode;
+    value = 37 * value + minHeight.hashCode;
+    value = 37 * value + maxHeight.hashCode;
+    return value;
+  }
+  String toString() => "BoxConstraints($minWidth<=w<$maxWidth, $minHeight<=h<$maxHeight)";
 }
 
 class BoxParentData extends ParentData {