Fix layout bug when there are no visible boxes (#8507)

Author: kurkle

src/core/core.layouts.js

@@ -344,7 +344,7 @@ export default {
     //
 
     const visibleVerticalBoxCount = verticalBoxes.reduce((total, wrap) =>
-      wrap.box.options && wrap.box.options.display === false ? total : total + 1, 0);
+      wrap.box.options && wrap.box.options.display === false ? total : total + 1, 0) || 1;
 
     const params = Object.freeze({
       outerWidth: width,

test/fixtures/core.layouts/no-boxes-all-padding.js

@@ -0,0 +1,39 @@
+module.exports = {
+  config: {
+    type: 'line',
+    data: {
+      labels: [0],
+      datasets: [{
+        data: [0],
+        radius: 16,
+        backgroundColor: 'red'
+      }],
+    },
+    options: {
+      plugins: {
+        legend: false,
+        tooltip: false,
+        title: false,
+        filler: false
+      },
+      scales: {
+        x: {
+          display: false,
+          offset: true
+        },
+        y: {
+          display: false
+        }
+      },
+      layout: {
+        padding: 16
+      }
+    }
+  },
+  options: {
+    canvas: {
+      height: 32,
+      width: 32
+    }
+  }
+};