Issue #1619 - Convert Intrinsic Ratio to Float

https://bugzilla.mozilla.org/show_bug.cgi?id=1547792

Aspect Ratio handling simplified by using floating point integers:
- Multiplication of value (or inverse value) to a known side for Scaling
- No unequal equal values such as "4/3" vs "8/6" vs "20/15"
- Truly "Empty" aspect ratios, even if one dimension is not 0

layout/generic/nsLineLayout.cpp

@@ -784,7 +784,7 @@ IsPercentageAware(const nsIFrame* aFrame)
     //   is calculated from the constraint equation used for
     //   block-level, non-replaced elements in normal flow. 
     nsIFrame *f = const_cast<nsIFrame*>(aFrame);
-    if (f->GetIntrinsicRatio() != nsSize(0, 0) &&
+    if (f->GetIntrinsicRatio() &&
         // Some percents are treated like 'auto', so check != coord
         pos->mHeight.GetUnit() != eStyleUnit_Coord) {
       const IntrinsicSize &intrinsicSize = f->GetIntrinsicSize();