add 'some' mapbox-gl css rule

... mostly to hide mapbox-gl's own no-css warning
    that get injected into the DOM.

Author: etpinard

src/plots/mapbox/constants.js

@@ -32,5 +32,11 @@ module.exports = {
         'More info here: https://www.mapbox.com/help/define-access-token/'
     ].join('\n'),
 
-    mapOnErrorMsg: 'Mapbox error.'
+    mapOnErrorMsg: 'Mapbox error.',
+
+    // a subset of node_modules/mapbox-gl/dist/mapbox-gl.css
+    styleRules: {
+        map: 'overflow:hidden;position:relative;',
+        'missing-css': 'display:none',
+    }
 };

src/plots/mapbox/index.js

@@ -6,7 +6,6 @@
 * LICENSE file in the root directory of this source tree.
 */
 
-
 'use strict';
 
 var mapboxgl = require('mapbox-gl');
@@ -20,6 +19,9 @@ var constants = require('./constants');
 
 var MAPBOX = 'mapbox';
 
+for(var k in constants.styleRules) {
+    Lib.addStyleRule('.mapboxgl-' + k, constants.styleRules[k]);
+}
 
 exports.name = MAPBOX;