Use background property for vector layers

test/rendering/cases/layer-vector-background/main.js

@@ -0,0 +1,33 @@
+import GeoJSON from '../../../../src/ol/format/GeoJSON.js';
+import Map from '../../../../src/ol/Map.js';
+import VectorLayer from '../../../../src/ol/layer/Vector.js';
+import VectorSource from '../../../../src/ol/source/Vector.js';
+import View from '../../../../src/ol/View.js';
+import {Fill, Stroke, Style} from '../../../../src/ol/style.js';
+
+new Map({
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    zoom: 1,
+  }),
+  layers: [
+    new VectorLayer({
+      background: '#a9d3df',
+      source: new VectorSource({
+        url: '/data/countries.json',
+        format: new GeoJSON(),
+      }),
+      style: new Style({
+        stroke: new Stroke({
+          color: '#ccc',
+        }),
+        fill: new Fill({
+          color: 'white',
+        }),
+      }),
+    }),
+  ],
+});
+
+render();

test/rendering/cases/layer-vectorimage-background/main.js

@@ -0,0 +1,33 @@
+import GeoJSON from '../../../../src/ol/format/GeoJSON.js';
+import Map from '../../../../src/ol/Map.js';
+import VectorImageLayer from '../../../../src/ol/layer/VectorImage.js';
+import VectorSource from '../../../../src/ol/source/Vector.js';
+import View from '../../../../src/ol/View.js';
+import {Fill, Stroke, Style} from '../../../../src/ol/style.js';
+
+new Map({
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    zoom: 1,
+  }),
+  layers: [
+    new VectorImageLayer({
+      background: '#a9d3df',
+      source: new VectorSource({
+        url: '/data/countries.json',
+        format: new GeoJSON(),
+      }),
+      style: new Style({
+        stroke: new Stroke({
+          color: '#ccc',
+        }),
+        fill: new Fill({
+          color: 'white',
+        }),
+      }),
+    }),
+  ],
+});
+
+render();