Omnibox: Make the Controller Reorder Matches for Inlining

chrome/browser/autocomplete/autocomplete_result.cc

Index: chrome/browser/autocomplete/autocomplete_result.cc
diff --git a/chrome/browser/autocomplete/autocomplete_result.cc b/chrome/browser/autocomplete/autocomplete_result.cc
index 58a19c98b6bcbb4720141f66a1f0a0242b9b2706..537de0d8902029d06a374992f8bcbd12577a3fb6 100644
--- a/chrome/browser/autocomplete/autocomplete_result.cc
+++ b/chrome/browser/autocomplete/autocomplete_result.cc
@@ -10,6 +10,7 @@
 #include "base/logging.h"
 #include "chrome/browser/autocomplete/autocomplete_input.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
+#include "chrome/browser/omnibox/omnibox_field_trial.h"
 
 // static
 const size_t AutocompleteResult::kMaxMatches = 6;
@@ -21,7 +22,9 @@ void AutocompleteResult::Selection::Clear() {
   is_history_what_you_typed_match = false;
 }
 
-AutocompleteResult::AutocompleteResult() {
+AutocompleteResult::AutocompleteResult()
+    : reorder_for_legal_default_match_(
+          OmniboxFieldTrial::InReorderForLegalDefaultMatchGroup()) {
   // Reserve space for the max number of matches we'll show.
   matches_.reserve(kMaxMatches);
 
@@ -99,12 +102,23 @@ void AutocompleteResult::SortAndCull(const AutocompleteInput& input,
                  matches_.end());
 
   // Sort and trim to the most relevant kMaxMatches matches.
-  const size_t num_matches = std::min(kMaxMatches, matches_.size());
-  std::partial_sort(matches_.begin(), matches_.begin() + num_matches,
-                    matches_.end(), &AutocompleteMatch::MoreRelevant);
-  matches_.resize(num_matches);
+  std::sort(matches_.begin(), matches_.end(), &AutocompleteMatch::MoreRelevant);
+  if (!empty() && !begin()->allowed_to_be_default_match &&
+      reorder_for_legal_default_match_) {
+    // Top match is not allowed to be the default match.  Find the most
+    // relevance legal match and shift it to the front.
+    for (AutocompleteResult::iterator it = begin(); it != end(); ++it) {
+      if (it->allowed_to_be_default_match) {
+        std::rotate(matches_.begin(), it, it + 1);
+        break;
+      }
+    }
+  }
+  matches_.resize(std::min(kMaxMatches, matches_.size()));
 
   default_match_ = begin();
+  DCHECK((default_match_ == end()) ||
+      default_match_->allowed_to_be_default_match);
 
   // Set the alternate nav URL.
   alternate_nav_url_ = (default_match_ == end()) ?