[tracing] Move math utilities from base into their own subdirectory (attempt 2)

tracing/tracing/ui/side_panel/file_size_stats_side_panel.html

Index: tracing/tracing/ui/side_panel/file_size_stats_side_panel.html
diff --git a/tracing/tracing/ui/side_panel/file_size_stats_side_panel.html b/tracing/tracing/ui/side_panel/file_size_stats_side_panel.html
index 6de03542b15bfde6209bdabafd165110c3119024..46e7cad66613a2a9fea2634b07a0850aa8f4809f 100644
--- a/tracing/tracing/ui/side_panel/file_size_stats_side_panel.html
+++ b/tracing/tracing/ui/side_panel/file_size_stats_side_panel.html
@@ -5,8 +5,8 @@ Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
+<link rel="import" href="/tracing/base/math/statistics.html">
 <link rel="import" href="/tracing/base/scalar.html">
-<link rel="import" href="/tracing/base/statistics.html">
 <link rel="import" href="/tracing/base/unit.html">
 <link rel="import" href="/tracing/ui/base/grouping_table.html">
 <link rel="import" href="/tracing/ui/base/grouping_table_groupby_picker.html">
@@ -185,12 +185,12 @@ found in the LICENSE file.
 
       var columns = this.createColumns_(this.model.stats);
       table.rowStatsConstructor = function ModelStatsRowStats(row) {
-        var sum = tr.b.Statistics.sum(row.data, function(x) {
+        var sum = tr.b.math.Statistics.sum(row.data, function(x) {
           return x.numEvents;
         });
-        var totalEventSizeinBytes = tr.b.Statistics.sum(row.data, function(x) {
-          return x.totalEventSizeinBytes;
-        });
+        var totalEventSizeinBytes = tr.b.math.Statistics.sum(row.data, x =>
+          x.totalEventSizeinBytes
+        );
         return {
           numEvents: sum,
           totalEventSizeinBytes: totalEventSizeinBytes