Convert chart-json to Histograms.

tracing/tracing/ui/base/box_chart.html

Index: tracing/tracing/ui/base/box_chart.html
diff --git a/tracing/tracing/ui/base/box_chart.html b/tracing/tracing/ui/base/box_chart.html
index 6ed4b80fc20392da1aaedd53167f98b281e71284..fe8ae2001714ce80a25aa111d1543491528597ba 100644
--- a/tracing/tracing/ui/base/box_chart.html
+++ b/tracing/tracing/ui/base/box_chart.html
@@ -29,6 +29,18 @@ tr.exportTo('tr.ui.b', function() {
       this.xScale_.domain([0, this.data_.length]);
     },
 
+    updateDataRange_: function() {
+      if (this.overrideDataRange_ !== undefined) {
+        return;
+      }
+
+      this.autoDataRange_.reset();
+      for (var datum of this.data_) {
+        this.autoDataRange_.addValue(datum.percentile_0);
+        this.autoDataRange_.addValue(datum.percentile_100);
+      }
+    },
+
     updateXAxis_: function(xAxis) {
       xAxis.selectAll('*').remove();
       if (this.hideXAxis) {