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..981ad453ccc3e97947c39daf4b042501930ed16d 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;
@@ -99,12 +100,24 @@ 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);

[H Fung, 2013/08/06 22:03:17]

Nit: Since you use begin() and end() below, maybe be consistent here?
(I also don't see how the existing sorting function worked since it only sorted
the first num_matches after being sorted based on destination url)

[Mark P, 2013/08/06 22:18:06]

Switched below to matches_ to be consistent with the rest of this function that
I didn't trust.
Look again at the original sorting function AutocompleteMatch::MoreRelevant.  It
sorts by relevance, breaking ties by destination URL.

[H Fung, 2013/08/06 22:53:00]

I meant that AutocompleteMatch::DestinationSortFunc used to sort |matches_|
based on destination URL.  After that, only the first num_matches matches get
partially sorted using AutocompleteMatch::MoreRelevant.  So I'm not sure how a
high-scoring match with a URL like zillow would get sorted properly in this
function.

[Mark P, 2013/08/07 00:44:31]

I think you don't understand what partial_sort does.
http://www.cplusplus.com/reference/algorithm/partial_sort/

It sorts the array enough so that highest X matches are put at the beginning, in
order.

+  if (!empty() && !begin()->allowed_to_be_default_match &&
+      OmniboxFieldTrial::ReorderForLegalDefaultMatch(
+          input.current_page_classification())) {
+    // 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() + 1; 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()) ||

[H Fung, 2013/08/06 22:03:17]

I'm not sure, so feel free to ignore, but maybe empty() might be clearer than
(default_match_ == end())

[Mark P, 2013/08/06 22:18:06]

I can't do
default_match_.empty()
because default_match_ is an iterator, not the underlying vector.

I could do matches_.empty() but I think using default_match_ makes things
clearer that this is an assortment about, well, default_match_.

+      default_match_->allowed_to_be_default_match);
 
   // Set the alternate nav URL.
   alternate_nav_url_ = (default_match_ == end()) ?