Bug 1790167 - Simplify aspect-ratio code for outer svg. r=TYLin

Drive-by, but this should be more correct, since I'm not sure how this
code would handle mSVGView otherwise, which is in effect on the relevant
page.

Differential Revision: https://phabricator.services.mozilla.com/D157022

layout/svg/SVGOuterSVGFrame.cpp

@@ -114,7 +114,7 @@ void SVGOuterSVGFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
   // prevent them from painting by [ab]use NS_FRAME_IS_NONDISPLAY. The
   // frame will be recreated via an nsChangeHint_ReconstructFrame restyle if
   // the value returned by PassesConditionalProcessingTests changes.
-  SVGSVGElement* svg = static_cast<SVGSVGElement*>(aContent);
+  auto* svg = static_cast<SVGSVGElement*>(aContent);
   if (!svg->PassesConditionalProcessingTests()) {
     AddStateBits(NS_FRAME_IS_NONDISPLAY);
   }
@@ -243,11 +243,8 @@ AspectRatio SVGOuterSVGFrame::GetIntrinsicRatio() const {
   // We only have an intrinsic size/ratio if our width and height attributes
   // are both specified and set to non-percentage values, or we have a viewBox
   // rect: https://svgwg.org/svg2-draft/coords.html#SizingSVGInCSS
-  // Unfortunately we have to return the ratio as two nscoords whereas what
-  // we have are two floats. Using app units allows for some floating point
-  // values to work but really small or large numbers will fail.
 
-  SVGSVGElement* content = static_cast<SVGSVGElement*>(GetContent());
+  auto* content = static_cast<SVGSVGElement*>(GetContent());
   const SVGAnimatedLength& width =
       content->mLengthAttributes[SVGSVGElement::ATTR_WIDTH];
   const SVGAnimatedLength& height =
@@ -265,18 +262,10 @@ AspectRatio SVGOuterSVGFrame::GetIntrinsicRatio() const {
     }
   }
 
-  SVGViewElement* viewElement = content->GetCurrentViewElement();
-  const SVGViewBox* viewbox = nullptr;
-
-  // The logic here should match HasViewBox().
-  if (viewElement && viewElement->mViewBox.HasRect()) {
-    viewbox = &viewElement->mViewBox.GetAnimValue();
-  } else if (content->mViewBox.HasRect()) {
-    viewbox = &content->mViewBox.GetAnimValue();
-  }
-
-  if (viewbox) {
-    return AspectRatio::FromSize(viewbox->width, viewbox->height);
+  const auto& viewBox = content->GetViewBoxInternal();
+  if (viewBox.HasRect()) {
+    const auto& anim = viewBox.GetAnimValue();
+    return AspectRatio::FromSize(anim.width, anim.height);
   }
 
   return SVGDisplayContainerFrame::GetIntrinsicRatio();