Don't demote top match for certain match types.

chrome/browser/autocomplete/autocomplete_match.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_MATCH_H_
 #define CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_MATCH_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 253 matching lines @@
   // default match.  Providers should set this to true only if the
   // user's input, plus any inline autocompletion on this match, would
   // lead the user to expect a navigation to this match's destination.
   // For example, with input "foo", a search for "bar" or navigation
   // to "bar.com" should not set this flag; a navigation to "foo.com"
   // should only set this flag if ".com" will be inline autocompleted;
   // and a navigation to "foo/" (an intranet host) or search for "foo"
   // should set this flag.
   bool allowed_to_be_default_match;
 
+  // If the match should be allowed to be demoted by OmniboxBundleV1 ranking
+  // experiments.
+  bool demoteable;
+
   // The URL to actually load when the autocomplete item is selected. This URL
   // should be canonical so we can compare URLs with strcmp to avoid dupes.
   // It may be empty if there is no possible navigation.
   GURL destination_url;
 
   // The destination URL with "www." stripped off for better dupe finding.
   GURL stripped_destination_url;
 
   // The main text displayed in the address bar dropdown.
   string16 contents;
@@ skipping 61 matching lines @@
       const string16& text,
       const ACMatchClassifications& classifications) const;
 #endif
 };
 
 typedef AutocompleteMatch::ACMatchClassification ACMatchClassification;
 typedef std::vector<ACMatchClassification> ACMatchClassifications;
 typedef std::vector<AutocompleteMatch> ACMatches;
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_MATCH_H_