predictors: Use redirect data in prefetch.

chrome/browser/predictors/resource_prefetch_predictor_tables.cc

Index: chrome/browser/predictors/resource_prefetch_predictor_tables.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_tables.cc b/chrome/browser/predictors/resource_prefetch_predictor_tables.cc
index be1d55179a18c18842b1201b74fe6a1d9f34c524..4e983f6461a1a9e110e08e4ed18c39d0c713d794 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_tables.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_tables.cc
@@ -374,8 +374,8 @@ float ResourcePrefetchPredictorTables::ComputeResourceScore(
 // static
 float ResourcePrefetchPredictorTables::ComputeRedirectScore(
     const RedirectStat& data) {
-  // TODO(alexilin): Invent some scoring.
-  return 0.0;
+  return (data.number_of_hits() + 0.0) /
+         (data.number_of_hits() + data.number_of_misses());

[pasko, 2016/10/07 11:42:43]

If this is not covered by any tests, it would be nice to create once: populate
redirect tables, read back the redirects and check for their order.

[alexilin, 2016/10/07 13:09:29]

I've just realized that we don't have to sort redirects because we need only the
best one for populating prefetch. It could be done by single pass through the
array instead of (potentially) n*log(n) sorting.
So I removed this code.

 }
 
 // static