Bug 1542646 Part 6 - pass by reference when it's more efficient r=dholbert

layout/svg/nsCSSClipPathInstance.h

@@ -33,7 +33,7 @@ class nsCSSClipPathInstance {
 
  private:
   explicit nsCSSClipPathInstance(nsIFrame* aFrame,
-                                 const StyleShapeSource aClipPathStyle)
+                                 const StyleShapeSource& aClipPathStyle)
       : mTargetFrame(aFrame), mClipPathStyle(aClipPathStyle) {}
 
   already_AddRefed<Path> CreateClipPath(DrawTarget* aDrawTarget);

layout/svg/nsSVGPatternFrame.cpp

@@ -636,7 +636,7 @@ gfxMatrix nsSVGPatternFrame::ConstructCTM(const SVGAnimatedViewBox &aViewBox,
   if (!aViewBox.IsExplicitlySet()) {
     return gfxMatrix(scaleX, 0.0, 0.0, scaleY, 0.0, 0.0);
   }
-  const SVGViewBox viewBox = aViewBox.GetAnimValue();
+  const SVGViewBox& viewBox = aViewBox.GetAnimValue();
 
   if (viewBox.height <= 0.0f || viewBox.width <= 0.0f) {
     return gfxMatrix(0.0, 0.0, 0.0, 0.0, 0.0, 0.0);  // singular