Use the viewBox when scaling <svg:image>s non-uniformly w/ pAR=none

Source/platform/graphics/Image.h

Index: Source/platform/graphics/Image.h
diff --git a/Source/platform/graphics/Image.h b/Source/platform/graphics/Image.h
index 8b40396bd8cf139bffc80e43e53e2471367d7625..6c9cef8f3bd81f56d323c99a9ef22a4266230ef4 100644
--- a/Source/platform/graphics/Image.h
+++ b/Source/platform/graphics/Image.h
@@ -84,6 +84,10 @@ public:
     virtual bool usesContainerSize() const { return false; }
     virtual bool hasRelativeWidth() const { return false; }
     virtual bool hasRelativeHeight() const { return false; }
+
+    // Computes (extracts) the intrinsic dimensions and ratio from the Image. The intrinsic ratio
+    // will be the 'viewport' of the image. (Same as the dimensions for a raster image. For SVG
+    // images it can be the dimensions defined by the 'viewBox'.)
     virtual void computeIntrinsicDimensions(Length& intrinsicWidth, Length& intrinsicHeight, FloatSize& intrinsicRatio);
 
     virtual IntSize size() const = 0;