[Explore] Streamlined metric definitions for SQLA and Druid (#4663)

* adding streamlined metric editing

* addressing lint issues on new metrics control

* enabling druid

superset/assets/javascripts/explore/components/MetricDefinitionValue.jsx

@@ -0,0 +1,47 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+
+import AdhocMetricOption from './AdhocMetricOption';
+import AdhocMetric from '../AdhocMetric';
+import columnType from '../propTypes/columnType';
+import MetricOption from '../../components/MetricOption';
+import savedMetricType from '../propTypes/savedMetricType';
+import adhocMetricType from '../propTypes/adhocMetricType';
+
+const propTypes = {
+  option: PropTypes.oneOfType([
+    savedMetricType,
+    adhocMetricType,
+  ]).isRequired,
+  onMetricEdit: PropTypes.func,
+  columns: PropTypes.arrayOf(columnType),
+  multi: PropTypes.bool,
+  datasourceType: PropTypes.string,
+};
+
+export default function MetricDefinitionValue({
+  option,
+  onMetricEdit,
+  columns,
+  multi,
+  datasourceType,
+}) {
+  if (option.metric_name) {
+    return (
+      <MetricOption metric={option} />
+    );
+  } else if (option instanceof AdhocMetric) {
+    return (
+      <AdhocMetricOption
+        adhocMetric={option}
+        onMetricEdit={onMetricEdit}
+        columns={columns}
+        multi={multi}
+        datasourceType={datasourceType}
+      />
+    );
+  }
+  notify.error('You must supply either a saved metric or adhoc metric to MetricDefinitionValue');
+  return null;
+}
+MetricDefinitionValue.propTypes = propTypes;