Ensure baselayers display in region maps (#22609)

* Add tmsLayers placeholder array to collections. Bind collections to wms-options scope

* Move tmsLayers attribute declaration to base visualization creation

* Add test to verify presence of road_map base layer option

src/core_plugins/region_map/public/region_map_vis.js

@@ -77,7 +77,8 @@ provided base maps, or add your own. Darker colors represent higher values.' }),
           text: i18n('regionMap.mapVis.regionMapEditorConfig.topRightText', { defaultMessage: 'top right' }),
         }],
         colorSchemas: Object.values(truncatedColorMaps).map(value => ({ id: value.id, label: value.label })),
-        vectorLayers: vectorLayers
+        vectorLayers: vectorLayers,
+        tmsLayers: []
       },
       schemas: new Schemas([
         {

src/core_plugins/region_map/public/region_map_vis_params.html

@@ -150,4 +150,4 @@
   </div>
 </div>
 
-<wms-options options="editorState.params.wms"></wms-options>
+<wms-options options="editorState.params.wms" collections="collections"></wms-options>

test/functional/apps/visualize/_region_map.js

@@ -27,6 +27,7 @@ export default function ({ getService, getPageObjects }) {
     const toTime = '2015-09-23 18:31:44.000';
 
     const log = getService('log');
+    const find = getService('find');
     const PageObjects = getPageObjects(['common', 'visualize', 'header', 'settings']);
 
     before(async function () {
@@ -73,17 +74,19 @@ export default function ({ getService, getPageObjects }) {
         await  PageObjects.visualize.selectFieldById('Three letter abbreviation', 'joinField');
         await  PageObjects.visualize.selectFieldById('Country name', 'joinField');
         await  PageObjects.visualize.selectFieldById('Two letter abbreviation', 'joinField');
-
         await PageObjects.common.sleep(2000);//need some time for the data to load
 
         await PageObjects.visualize.openInspector();
         const actualData = await PageObjects.visualize.getInspectorTableData();
         const expectedData = [['CN', '2,592'], ['IN', '2,373'], ['US', '1,194'], ['ID', '489'], ['BR', '415']];
         expect(actualData).to.eql(expectedData);
-
-
       });
 
+      it('should contain a dropdown with the default road_map base layer as an option',
+        async () => {
+          const roadMapExists = await find.existsByCssSelector('[label="road_map"]');
+          expect(roadMapExists).to.be(true);
+        });
     });
   });