Revert "Remove Continuous vars with 1 value from histogram, add to info drawer (#1927)" (#1953)

This reverts commit 242546371b.

client/src/components/brushableHistogram/index.js

@@ -450,7 +450,6 @@ const Histogram = ({
     isScatterplotYYaccessor: state.controls.scatterplotYYaccessor === field,
     continuousSelectionRange: state.continuousSelection[myName],
     isColorAccessor: state.colors.colorAccessor === field,
-    singleContinuousValues: state.singleContinuousValue.singleContinuousValues,
   };
 })
 class HistogramBrush extends React.PureComponent {
@@ -609,44 +608,18 @@ class HistogramBrush extends React.PureComponent {
   };
 
   fetchAsyncProps = async () => {
-    const { annoMatrix, field, dispatch, singleContinuousValues } = this.props;
+    const { annoMatrix } = this.props;
     const { isClipped } = annoMatrix;
-    if (singleContinuousValues.has(field)) {
-      return {
-        histogram: undefined,
-        range: undefined,
-        unclippedRange: undefined,
-        unclippedRangeColor: globals.blue,
-        isSingleValue: true,
-        OK2Render: false,
-      };
-    }
+
     const query = this.createQuery();
     const df = await annoMatrix.fetch(...query);
     const column = df.icol(0);
 
+    // if we are clipped, fetch both our value and our unclipped value,
+    // as we need the absolute min/max range, not just the clipped min/max.
     const summary = column.summarize();
     const range = [summary.min, summary.max];
 
-    if (summary.min === summary.max && !isClipped) {
-      dispatch({
-        type: "add single continuous value",
-        field,
-        value: summary.min,
-      });
-      return {
-        histogram: undefined,
-        range,
-        unclippedRange: range,
-        unclippedRangeColor: globals.blue,
-        isSingleValue: true,
-        OK2Render: false,
-      };
-    }
-
-    const isSingleValue = summary.min === summary.max;
-    // if we are clipped, fetch both our value and our unclipped value,
-    // as we need the absolute min/max range, not just the clipped min/max.
     let unclippedRange = [...range];
     if (isClipped) {
       const parent = await annoMatrix.viewOf.fetch(...query);
@@ -670,6 +643,7 @@ class HistogramBrush extends React.PureComponent {
       this.height
     );
 
+    const isSingleValue = summary.min === summary.max;
     const nonFiniteExtent =
       summary.min === undefined ||
       summary.max === undefined ||