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

image/ClippedImage.cpp

@@ -242,13 +242,13 @@ ClippedImage::GetIntrinsicSize(nsSize* aSize)
 }
 
 NS_IMETHODIMP
-ClippedImage::GetIntrinsicRatio(nsSize* aRatio)
+ClippedImage::GetIntrinsicRatio(AspectRatio* aRatio)
 {
   if (!ShouldClip()) {
     return InnerImage()->GetIntrinsicRatio(aRatio);
   }
 
-  *aRatio = nsSize(mClip.width, mClip.height);
+  *aRatio = AspectRatio::FromSize(mClip.width, mClip.height);
   return NS_OK;
 }