Omnibox: Make the Controller Reorder Matches for Inlining

chrome/browser/autocomplete/search_provider.cc

Index: chrome/browser/autocomplete/search_provider.cc
diff --git a/chrome/browser/autocomplete/search_provider.cc b/chrome/browser/autocomplete/search_provider.cc
index 2f304504aedc799592c70a674e19c82aaa784837..5dca8c30f0291e0753d3d12cd498edb7bca6abbc 100644
--- a/chrome/browser/autocomplete/search_provider.cc
+++ b/chrome/browser/autocomplete/search_provider.cc
@@ -255,7 +255,9 @@ SearchProvider::SearchProvider(AutocompleteProviderListener* listener,
       prevent_search_history_inlining_(
           OmniboxFieldTrial::SearchHistoryPreventInlining()),
       disable_search_history_(
-          OmniboxFieldTrial::SearchHistoryDisable()) {
+          OmniboxFieldTrial::SearchHistoryDisable()),
+      omnibox_will_reorder_for_legal_default_match_(
+          OmniboxFieldTrial::InReorderForLegalDefaultMatchGroup()) {
 }
 
 // static
@@ -315,6 +317,7 @@ AutocompleteMatch SearchProvider::CreateSearchSuggestion(
     // completion.
     match.contents_class.push_back(
         ACMatchClassification(0, ACMatchClassification::NONE));
+    match.allowed_to_be_default_match = true;
   }
 
   // When the user forced a query, we need to make sure all the fill_into_edit
@@ -328,6 +331,7 @@ AutocompleteMatch SearchProvider::CreateSearchSuggestion(
       StartsWith(query_string, input_text, false)) {
     match.inline_autocomplete_offset =
         match.fill_into_edit.length() + input_text.length();
+    match.allowed_to_be_default_match = true;
   }
   match.fill_into_edit.append(query_string);
 
@@ -1072,15 +1076,17 @@ bool SearchProvider::IsTopMatchHighRankSearchForURL() const {
           matches_.front().type == AutocompleteMatchType::SEARCH_OTHER_ENGINE);
 }
 
-bool SearchProvider::IsTopMatchNotInlinable() const {
-  // Note: this test assumes the SEARCH_OTHER_ENGINE match corresponds to
-  // the verbatim search query on the keyword engine.  SearchProvider should
-  // not create any other match of type SEARCH_OTHER_ENGINE.
-  return
-      matches_.front().type != AutocompleteMatchType::SEARCH_WHAT_YOU_TYPED &&
-      matches_.front().type != AutocompleteMatchType::SEARCH_OTHER_ENGINE &&
-      matches_.front().inline_autocomplete_offset == string16::npos &&
-      matches_.front().fill_into_edit != input_.text();
+bool SearchProvider::IsTopMatchNotAllowedToBeDefaultMatch() const {
+  return !matches_.front().allowed_to_be_default_match;
+}
+
+bool SearchProvider::LacksDefaultMatch() const {
+  for (ACMatches::const_iterator it = matches_.begin(); it != matches_.end();
+       ++it) {
+    if (it->allowed_to_be_default_match)
+      return false;
+  }
+  return true;
 }
 
 void SearchProvider::UpdateMatches() {
@@ -1125,18 +1131,32 @@ void SearchProvider::UpdateMatches() {
       keyword_results_.verbatim_relevance = -1;
       ConvertResultsToAutocompleteMatches();
     }
-    if (IsTopMatchNotInlinable()) {
-      // Disregard suggested relevances if the top match is not a verbatim match
-      // or inlinable.  For example, input "foo" should not invoke a search for
-      // "bar", which would happen if the "bar" search match outranked all other
-      // matches.
+    if ((!omnibox_will_reorder_for_legal_default_match_ &&

[Peter Kasting, 2013/07/17 18:29:48]

Nit: Simpler:

    if (omnibox_will_reorder_for_legal_default_match_ ?
        LacksDefaultMatch() : IsTopMatchNotAllowedToBeDefaultMatch())

[Mark P, 2013/07/17 20:39:18]

Done.

+         IsTopMatchNotAllowedToBeDefaultMatch()) ||
+        (omnibox_will_reorder_for_legal_default_match_ &&
+         LacksDefaultMatch())) {
+      // Disregard suggested relevances if either:
+      // * the top match is not allowed to be the default match (i.e., it's not
+      //   either a verbatim match or inlinable).  For example, input "foo"
+      //   should not invoke a search for "bar", which would happen if the
+      //   "bar" search match outranked all other matches.  We only care
+      //   about this condition if the omnibox itself will not reorder
+      //   matches to put a legal default match on top.
+      // * no matches are allowed to be the default match.  SearchProvider is
+      //   supposed to return a legal default match for any input.  We need
+      //   to make sure it does so.  This constraint should be true always,
+      //   but we only need to check it if
+      //   |omnibox_will_reorder_for_legal_default_match_|.  (If that were
+      //   false, the first part of the test above will suffice.)
       ApplyCalculatedRelevance();
       ConvertResultsToAutocompleteMatches();
     }
     DCHECK(!IsTopMatchNavigationInKeywordMode());
     DCHECK(!IsTopMatchScoreTooLow());
     DCHECK(!IsTopMatchHighRankSearchForURL());
-    DCHECK(!IsTopMatchNotInlinable());
+    DCHECK(omnibox_will_reorder_for_legal_default_match_ ||
+           !IsTopMatchNotAllowedToBeDefaultMatch());
+    DCHECK(!LacksDefaultMatch());
   }
 
   UpdateStarredStateOfMatches();