Omnibox: Prevent Asynchronous Suggestions from Changing Default Match

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 bf49576093038dd465cd265dc23fb206c6212e35..30fb42ecb2475daa7e6efa07411113ee9be237a8 100644
--- a/chrome/browser/autocomplete/search_provider.cc
+++ b/chrome/browser/autocomplete/search_provider.cc
@@ -260,6 +260,16 @@ void SearchProvider::Start(const AutocompleteInput& input,
 
   input_ = input;
 
+  // If Start() is called without minimal_changes, it likely means the user
+  // has pressed a key.  This is a good opportunity to change the inline
+  // autocompletion (if any).  Restore the results to the original reply
+  // received from the server, thus clobbering any modification (if any) made
+  // to the results to demote an brand new async inline autocompletion.
+  if (!minimal_changes) {
+    default_results_ = orig_default_results_;
+    keyword_results_ = orig_keyword_results_;
+  }
+
   DoHistoryQuery(minimal_changes);
   DoAnswersQuery(input);
   StartOrStopSuggestQuery(minimal_changes);
@@ -304,7 +314,60 @@ const AutocompleteInput SearchProvider::GetInput(bool is_keyword) const {
 
 SearchSuggestionParser::Results* SearchProvider::GetResultsToFill(
     bool is_keyword) {
-  return is_keyword ? &keyword_results_ : &default_results_;
+  return is_keyword ? &orig_keyword_results_ : &orig_default_results_;
+}
+
+void SearchProvider::HandleReceivedResults(bool is_keyword) {
+  // The general strategy of this function:
+  // 1.  Get the needed information from the previously-displayed results.
+  // 2.  Copy the newly-received results over the previously-displayed ones.
+  // 3.  Modify these results as necessary.
+
+  // 1.  Extract needed information.
+  // Determine the previous inline autocompletion, if any.
+  // We store the inlined suggestion (if any) in one of the two following
+  // variables, leaving them blank if there is no inline suggestion or the
+  // inlined suggestion is not of that type.
+  base::string16 inlined_query_suggestion_match_contents;
+  GURL inlined_navsuggestion;
+  ACMatches::const_iterator first_match = FindTopMatch();
+  if ((first_match != matches_.end()) &&
+      !first_match->inline_autocompletion.empty()) {
+    // Identify if this match came from a query suggestion or a navsuggestion.
+    // In either case, extracts the identifying feature of the suggestion
+    // (query string or navigation url).
+    if (AutocompleteMatch::IsSearchType(first_match->type)) {
+      inlined_query_suggestion_match_contents = first_match->contents;
+    } else {
+      inlined_navsuggestion = first_match->destination_url;
+    }
+  }
+
+  // 2.  Clobber the previous results.
+  SearchSuggestionParser::Results* results_from_server =
+      is_keyword ? &orig_keyword_results_ : &orig_default_results_;
+  SearchSuggestionParser::Results* results =
+      is_keyword ? &keyword_results_ : &default_results_;
+  (*results) = (*results_from_server);
+
+  // 3.  Modify the results.
+  // Mark all results aside from the previous inline autocompletion as not
+  // allowed to be the default match.
+  for (SearchSuggestionParser::SuggestResults::iterator sug_it =
+           results->suggest_results.begin();
+       sug_it != results->suggest_results.end(); ++sug_it) {
+    if (sug_it->match_contents() !=
+        inlined_query_suggestion_match_contents) {
+      sug_it->set_never_allowed_to_be_default_match(true);
+    }
+  }
+  for (SearchSuggestionParser::NavigationResults::iterator nav_it =
+           results->navigation_results.begin();
+       nav_it != results->navigation_results.end(); ++nav_it) {
+    if (nav_it->url() != inlined_navsuggestion) {
+      nav_it->set_never_allowed_to_be_default_match(true);
+    }
+  }
 }
 
 bool SearchProvider::ShouldAppendExtraParams(
@@ -328,6 +391,8 @@ void SearchProvider::StopSuggest() {
 void SearchProvider::ClearAllResults() {
   keyword_results_.Clear();
   default_results_.Clear();
+  orig_keyword_results_.Clear();
+  orig_default_results_.Clear();
 }
 
 int SearchProvider::GetDefaultResultRelevance() const {
@@ -624,6 +689,7 @@ void SearchProvider::ApplyCalculatedSuggestRelevance(
         result.CalculateRelevance(input_, providers_.has_keyword_provider()) +
         (list->size() - i - 1));
     result.set_relevance_from_server(false);
+    result.set_never_allowed_to_be_default_match(false);
   }
 }
 
@@ -635,6 +701,7 @@ void SearchProvider::ApplyCalculatedNavigationRelevance(
         result.CalculateRelevance(input_, providers_.has_keyword_provider()) +
         (list->size() - i - 1));
     result.set_relevance_from_server(false);
+    result.set_never_allowed_to_be_default_match(false);
   }
 }
 
@@ -1174,7 +1241,9 @@ AutocompleteMatch SearchProvider::NavigationToMatch(
   // that we're not preventing, make sure we didn't trim any whitespace.
   // We don't want to claim http://foo.com/bar is inlineable against the
   // input "foo.com/b ".
-  match.allowed_to_be_default_match = (prefix != NULL) &&
+  match.allowed_to_be_default_match =
+      !navigation.never_allowed_to_be_default_match() &&
+      (prefix != NULL) &&
       (providers_.GetKeywordProviderURL() == NULL) &&
       (match.inline_autocompletion.empty() ||
       (!input_.prevent_inline_autocomplete() && !trimmed_whitespace));