SIP-32: Moving frontend code to the base of the repo (#9098)

* move assets out, get webpack dev working

* update docs to reference superset-frontend

* draw the rest of the owl

* fix docs

* fix webpack script

* rats

* correct docs

* fix tox dox

superset-frontend/spec/javascripts/dashboard/helpers/WithDragDropContext.jsx

@@ -0,0 +1,45 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import React from 'react';
+import PropTypes from 'prop-types';
+
+import getDragDropManager from '../../../../src/dashboard/util/getDragDropManager';
+
+// A helper component that provides a DragDropContext for components that require it
+class WithDragDropContext extends React.Component {
+  getChildContext() {
+    return {
+      dragDropManager: this.context.dragDropManager || getDragDropManager(),
+    };
+  }
+
+  render() {
+    return this.props.children;
+  }
+}
+
+WithDragDropContext.propTypes = {
+  children: PropTypes.node.isRequired,
+};
+
+WithDragDropContext.childContextTypes = {
+  dragDropManager: PropTypes.object.isRequired,
+};
+
+export default WithDragDropContext;