Don't demote top match for certain match types.

chrome/browser/omnibox/omnibox_field_trial.cc

Index: chrome/browser/omnibox/omnibox_field_trial.cc
diff --git a/chrome/browser/omnibox/omnibox_field_trial.cc b/chrome/browser/omnibox/omnibox_field_trial.cc
index e2c7144101483c2a6f0528524ec7d2854d086458..6b9510b623d526f1e7907b4750832b896f2eb825 100644
--- a/chrome/browser/omnibox/omnibox_field_trial.cc
+++ b/chrome/browser/omnibox/omnibox_field_trial.cc
@@ -254,7 +254,7 @@ void OmniboxFieldTrial::GetDemotionsByType(
     for (base::StringPairs::const_iterator it = kv_pairs.begin();
          it != kv_pairs.end(); ++it) {
       // This is a best-effort conversion; we trust the hand-crafted parameters
-      // downloaded from the server to be perfect.  There's no need for handle
+      // downloaded from the server to be perfect.  There's no need to handle
       // errors smartly.
       int k, v;
       base::StringToInt(it->first, &k);
@@ -265,6 +265,32 @@ void OmniboxFieldTrial::GetDemotionsByType(
   }
 }
 
+OmniboxFieldTrial::UndemotableTopMatchTypes
+OmniboxFieldTrial::GetUndemotableTopTypes(
+    AutocompleteInput::PageClassification current_page_classification) {
+  UndemotableTopMatchTypes undemotable_types;
+  const std::string types_rule =
+      OmniboxFieldTrial::GetValueForRuleInContext(
+          kUndemotableTopTypeRule,
+          current_page_classification);
+  // The value of the UndemotableTopTypes rule is a comma-separated list of
+  // AutocompleteMatchType::Type enums represented as an integer. The
+  // DemoteByType rule does not apply to the top match if the type of the top
+  // match is in this list.
+  std::vector<std::string> types;
+  base::SplitString(types_rule, ',', &types);
+  for (std::vector<std::string>::const_iterator it = types.begin();
+       it != types.end(); ++it) {
+    // This is a best-effort conversion; we trust the hand-crafted parameters
+    // downloaded from the server to be perfect.  There's no need to handle
+    // errors smartly.
+    int t;
+    base::StringToInt(*it, &t);
+    undemotable_types.insert(static_cast<AutocompleteMatchType::Type>(t));
+  }
+  return undemotable_types;
+}
+
 bool OmniboxFieldTrial::ReorderForLegalDefaultMatch(
     AutocompleteInput::PageClassification current_page_classification) {
   return OmniboxFieldTrial::GetValueForRuleInContext(
@@ -278,6 +304,7 @@ const char OmniboxFieldTrial::kShortcutsScoringMaxRelevanceRule[] =
     "ShortcutsScoringMaxRelevance";
 const char OmniboxFieldTrial::kSearchHistoryRule[] = "SearchHistory";
 const char OmniboxFieldTrial::kDemoteByTypeRule[] = "DemoteByType";
+const char OmniboxFieldTrial::kUndemotableTopTypeRule[] = "UndemotableTopTypes";
 const char OmniboxFieldTrial::kReorderForLegalDefaultMatchRule[] =
     "ReorderForLegalDefaultMatch";
 const char OmniboxFieldTrial::kReorderForLegalDefaultMatchRuleEnabled[] =