Fix cross size of flex items in stocks app (more tests incoming)

sky/sdk/lib/framework/rendering/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:math' as math;
 import 'box.dart';
 import 'object.dart';
 
 class FlexBoxParentData extends BoxParentData with ContainerParentDataMixin<RenderBox> {
   int flex;
@@ skipping 212 matching lines @@
       constraints: constraints,
       sizingDirection: FlexDirection.vertical,
       childSize: (c, innerConstraints) => c.getMaxIntrinsicHeight(innerConstraints));
   }
 
   int _getFlex(RenderBox child) {
     assert(child.parentData is FlexBoxParentData);
     return child.parentData.flex != null ? child.parentData.flex : 0;
   }
 
+  double _getCrossSize(RenderBox child) {
+    return (_direction == FlexDirection.horizontal) ? child.size.height : child.size.width;
+  }
+
+  double _getMainSize(RenderBox child) {
+    return (_direction == FlexDirection.horizontal) ? child.size.width : child.size.height;
+  }
+
   void performLayout() {
     // Based on http://www.w3.org/TR/css-flexbox-1/ Section 9.7 Resolving Flexible Lengths
     // Steps 1-3. Determine used flex factor, size inflexible items, calculate free space
     int totalFlex = 0;
     int totalChildren = 0;
     assert(constraints != null);
     final double mainSize = (_direction == FlexDirection.horizontal) ? constraints.maxWidth : constraints.maxHeight;
     double crossSize = 0.0;  // This will be determined after laying out the children
     double freeSpace = mainSize;
     RenderBox child = firstChild;
     while (child != null) {
       totalChildren++;
       int flex = _getFlex(child);
       if (flex > 0) {
         totalFlex += child.parentData.flex;
       } else {
         BoxConstraints innerConstraints = new BoxConstraints(maxHeight: constraints.maxHeight,
                                                              maxWidth: constraints.maxWidth);
         child.layout(innerConstraints, parentUsesSize: true);
-        freeSpace -= (_direction == FlexDirection.horizontal) ? child.size.width : child.size.height;
+        freeSpace -= _getMainSize(child);
+        crossSize = math.max(crossSize, _getCrossSize(child));
       }
       child = child.parentData.nextSibling;
     }
 
     // Steps 4-5. Distribute remaining space to flexible children.
     double spacePerFlex = totalFlex > 0 ? (freeSpace / totalFlex) : 0.0;
     double usedSpace = 0.0;
     child = firstChild;
     while (child != null) {
       int flex = _getFlex(child);
       if (flex > 0) {
         double spaceForChild = spacePerFlex * flex;
         BoxConstraints innerConstraints;
         switch (_direction) {
           case FlexDirection.horizontal:
             innerConstraints = new BoxConstraints(maxHeight: constraints.maxHeight,
                                                   minWidth: spaceForChild,
                                                   maxWidth: spaceForChild);
-            child.layout(innerConstraints, parentUsesSize: true);
-            usedSpace += child.size.width;
-            crossSize = math.max(crossSize, child.size.height);
             break;
           case FlexDirection.vertical:
             innerConstraints = new BoxConstraints(minHeight: spaceForChild,
                                                   maxHeight: spaceForChild,
                                                   maxWidth: constraints.maxWidth);
-            child.layout(innerConstraints, parentUsesSize: true);
-            usedSpace += child.size.height;
-            crossSize = math.max(crossSize, child.size.width);
             break;
         }
+        child.layout(innerConstraints, parentUsesSize: true);
+        usedSpace += _getMainSize(child);
+        crossSize = math.max(crossSize, _getCrossSize(child));
       }
       child = child.parentData.nextSibling;
     }
 
     // Section 8.2: Axis Alignment using the justify-content property
     double remainingSpace = math.max(0.0, freeSpace - usedSpace);
     double leadingSpace;
     double betweenSpace;
     child = firstChild;
     switch (_justifyContent) {
@@ skipping 15 matching lines @@
         break;
       case FlexJustifyContent.spaceAround:
         betweenSpace = totalChildren > 0 ? remainingSpace / totalChildren : 0.0;
         leadingSpace = betweenSpace / 2.0;
         break;
     }
 
     switch (_direction) {
       case FlexDirection.horizontal:
         size = constraints.constrain(new Size(mainSize, crossSize));
+        crossSize = size.height;
         break;
       case FlexDirection.vertical:
         size = constraints.constrain(new Size(crossSize, mainSize));
+        crossSize = size.width;
         break;
     }
 
     // Position elements. For now, center the flex items in the cross direction
-    double mainDimPosition = leadingSpace;
+    double childMainPosition = leadingSpace;
     child = firstChild;
     while (child != null) {
+      double childCrossPosition = crossSize / 2.0 - _getCrossSize(child) / 2.0;
       switch (_direction) {
         case FlexDirection.horizontal:
-          child.parentData.position = new Point(mainDimPosition, size.height / 2.0 - child.size.height / 2.0);
-          mainDimPosition += child.size.width;
+          child.parentData.position = new Point(childMainPosition, childCrossPosition);
           break;
         case FlexDirection.vertical:
-          child.parentData.position = new Point(size.width / 2.0 - child.size.width / 2.0, mainDimPosition);
-          mainDimPosition += child.size.height;
+          child.parentData.position = new Point(childCrossPosition, childMainPosition);
           break;
       }
-      mainDimPosition += betweenSpace;
+      childMainPosition += _getMainSize(child) + betweenSpace;
       child = child.parentData.nextSibling;
     }
   }
 
   void hitTestChildren(HitTestResult result, { Point position }) {
     defaultHitTestChildren(result, position: position);
   }
 
   void paint(RenderObjectDisplayList canvas) {
     defaultPaint(canvas);
   }
 }