fallback to max-width and max-height if necessary

Author: antoinerg

src/plots/plots.js

@@ -1387,8 +1387,8 @@ plots.plotAutoSize = function plotAutoSize(gd, layout, fullLayout) {
         // but don't enforce any ratio restrictions
         var computedStyle = isPlotDiv ? window.getComputedStyle(gd) : {};
 
-        newWidth = parseFloat(computedStyle.width) || fullLayout.width;
-        newHeight = parseFloat(computedStyle.height) || fullLayout.height;
+        newWidth = parseFloat(computedStyle.width) || parseFloat(computedStyle.maxWidth) || fullLayout.width;
+        newHeight = parseFloat(computedStyle.height) || parseFloat(computedStyle.maxHeight) || fullLayout.height;
     }
 
     var minWidth = plots.layoutAttributes.width.min,