Fix main size calculation from the aspect ratio

Summary:
When the following conditions are met, the main size become smaller by the margins in the main axis.
* The aspect ratio is defined
* The main size is not defined
* The cross size is defined
* The main margin is defined

This is because the main margin size is not included when calculating the main size from the aspect ratio.
Closes facebook/yoga#715

Reviewed By: emilsjolander

Differential Revision: D6998988

Pulled By: priteshrnandgaonkar

fbshipit-source-id: f6f69c47ece17bd7c5e41517b96032bf0c149356

Yoga.cpp

@@ -1102,10 +1102,11 @@ static void YGNodeComputeFlexBasisForChild(const YGNodeRef node,
 
     if (!YGFloatIsUndefined(child->getStyle().aspectRatio)) {
       if (!isMainAxisRow && childWidthMeasureMode == YGMeasureModeExactly) {
-        childHeight = (childWidth - marginRow) / child->getStyle().aspectRatio;
+        childHeight = marginColumn +
+            (childWidth - marginRow) / child->getStyle().aspectRatio;
         childHeightMeasureMode = YGMeasureModeExactly;
       } else if (isMainAxisRow && childHeightMeasureMode == YGMeasureModeExactly) {
-        childWidth =
+        childWidth = marginRow +
             (childHeight - marginColumn) * child->getStyle().aspectRatio;
         childWidthMeasureMode = YGMeasureModeExactly;
       }