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

tracing/tracing/metrics/system_health/utils.html

Index: tracing/tracing/metrics/system_health/utils.html
diff --git a/tracing/tracing/metrics/system_health/utils.html b/tracing/tracing/metrics/system_health/utils.html
index 459f955f6c2a356fa79f552ba02187f9c1ab4b7b..5edbb6386a72fee4bd91456b60619244584b9ca9 100644
--- a/tracing/tracing/metrics/system_health/utils.html
+++ b/tracing/tracing/metrics/system_health/utils.html
@@ -12,8 +12,8 @@ found in the LICENSE file.
 tr.exportTo('tr.metrics.sh', function() {
   // Returns a weight for this score.
   // score should be a number between 0 and 1 inclusive.
-  // This function is expected to be passed to tr.b.Statistics.weightedMean as
-  // its weightCallback.
+  // This function is expected to be passed to tr.b.math.Statistics.weightedMean
+  // as its weightCallback.
   function perceptualBlend(ir, index, score) {
     // Lower scores are exponentially more important than higher scores
     // due to the Peak-end rule.