Clearing the underlying source's tiles while removing a layer. (mapbox#9305)

* clearing the underlying source's tiles while removing a layer.

* Removing the clear command since this is computationally expensive and also causing a glitch on the map once the tiles are cleared.

* Changing the name of the function to hasLayer to be more specific regarding the function

Author: sgolbabaei

src/source/tile.js

@@ -392,6 +392,8 @@ class Tile {
         const vtLayers = this.latestFeatureIndex.loadVTLayers();
 
         for (const id in this.buckets) {
+            if (!painter.style.hasLayer(id)) continue;
+
             const bucket = this.buckets[id];
             // Buckets are grouped by common source-layer
             const sourceLayerId = bucket.layers[0]['sourceLayer'] || '_geojsonTileLayer';

src/style/style.js

@@ -769,6 +769,17 @@ class Style extends Evented {
         return this._layers[id];
     }
 
+    /**
+     * checks if a specific layer is present within the style.
+     *
+     * @param {string} id - id of the desired layer
+     * @returns {boolean} a boolean specifying if the given layer is present
+     */
+    hasLayer(id: string): boolean {
+        const layerIds = Object.keys(this._layers);
+        return layerIds.includes(id, 0);
+    }
+
     setLayerZoomRange(layerId: string, minzoom: ?number, maxzoom: ?number) {
         this._checkLoaded();