Add confidence to AutocompleteMatch.

chrome/browser/autocomplete/history_quick_provider.cc

Index: chrome/browser/autocomplete/history_quick_provider.cc
diff --git a/chrome/browser/autocomplete/history_quick_provider.cc b/chrome/browser/autocomplete/history_quick_provider.cc
index 57c9d118d7fdbb0cd3e9acc7bcd6a1a5dc2a43db..e2b0b71c0854cb564bc560b1f43a3b27acb78267 100644
--- a/chrome/browser/autocomplete/history_quick_provider.cc
+++ b/chrome/browser/autocomplete/history_quick_provider.cc
@@ -112,9 +112,11 @@ void HistoryQuickProvider::DoAutocomplete() {
     const ScoredHistoryMatch& history_match(*match_iter);
     if (history_match.raw_score > 0) {
       AutocompleteMatch ac_match = QuickMatchToACMatch(
-          history_match,
+          history_match, matches,
           PreventInlineAutocomplete(autocomplete_input_),
           &max_match_score);
+      UMA_HISTOGRAM_COUNTS_100("Autocomplete.Confidence_HistoryQuick",
+                               ac_match.confidence * 100);
       matches_.push_back(ac_match);
     }

[mrossetti, 2011/08/09 23:40:43]

You could calculate the denominator here and save it as an instance variable.

[dominich, 2011/08/10 16:10:13]

See other comment regarding potential algorithm changes.

   }
@@ -126,15 +128,17 @@ const int HistoryQuickProvider::kMaxNonInliningScore =
 
 AutocompleteMatch HistoryQuickProvider::QuickMatchToACMatch(
     const ScoredHistoryMatch& history_match,
+    const ScoredHistoryMatches& history_matches,
     bool prevent_inline_autocomplete,
     int* max_match_score) {
   DCHECK(max_match_score);
   const history::URLRow& info = history_match.url_info;
   int score = CalculateRelevance(history_match, max_match_score);
-  AutocompleteMatch match(this, score, !!info.visit_count(),
+  float confidence = CalculateConfidence(history_match, history_matches);
+  AutocompleteMatch match(this, score, confidence, !!info.visit_count(),
                           history_match.url_matches.empty() ?
-                          AutocompleteMatch::HISTORY_URL :
-                          AutocompleteMatch::HISTORY_TITLE);
+                              AutocompleteMatch::HISTORY_URL :
+                              AutocompleteMatch::HISTORY_TITLE);
   match.destination_url = info.url();
   DCHECK(match.destination_url.is_valid());
 
@@ -201,6 +205,20 @@ int HistoryQuickProvider::CalculateRelevance(
 }
 
 // static
+float HistoryQuickProvider::CalculateConfidence(
+    const ScoredHistoryMatch& match,
+    const ScoredHistoryMatches& matches) {
+  float denominator = 0.0f;
+  for (ScoredHistoryMatches::const_iterator it = matches.begin();

[mrossetti, 2011/08/09 23:40:43]

Why not just calculate the 'denominator' up in DoAutocomplete() once all
qualifying matches have been collected?

+       it != matches.end(); ++it) {
+    denominator += it->raw_score;
+  }
+  DCHECK(denominator > 0);
+
+  return static_cast<float>(match.raw_score) / denominator;
+}
+
+// static
 ACMatchClassifications HistoryQuickProvider::SpansFromTermMatch(
     const history::TermMatches& matches,
     size_t text_length,