Omnibox UI Experiments: Add flag to change max autocomplete matches.

components/omnibox/browser/autocomplete_result.h

 // Copyright 2014 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 COMPONENTS_OMNIBOX_BROWSER_AUTOCOMPLETE_RESULT_H_
 #define COMPONENTS_OMNIBOX_BROWSER_AUTOCOMPLETE_RESULT_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 41 matching lines @@
     const AutocompleteProvider* provider_affinity;
 
     // True when this is the HistoryURLProvider's "what you typed" match.  This
     // can't be tracked using |destination_url| because its URL changes on every
     // keystroke, so if this is set, we'll preserve the selection by simply
     // choosing the new "what you typed" entry and ignoring |destination_url|.
     bool is_history_what_you_typed_match;
   };
 
   // Max number of matches we'll show from the various providers.
-  static const size_t kMaxMatches;
+  static size_t GetMaxMatches();
 
   AutocompleteResult();
   ~AutocompleteResult();
 
   // Copies matches from |old_matches| to provide a consistant result set. See
   // comments in code for specifics.
   void CopyOldMatches(const AutocompleteInput& input,
                       const AutocompleteResult& old_matches,
                       TemplateURLService* template_url_service);
 
   // Adds a new set of matches to the result set.  Does not re-sort.  Calls
   // PossiblySwapContentsAndDescriptionForURLSuggestion(input)" on all added
   // matches; see comments there for more information.
   void AppendMatches(const AutocompleteInput& input,
                      const ACMatches& matches);
 
   // Removes duplicates, puts the list in sorted order and culls to leave only
-  // the best kMaxMatches matches.  Sets the default match to the best match
+  // the best GetMaxMatches() matches.  Sets the default match to the best match
   // and updates the alternate nav URL.
   void SortAndCull(const AutocompleteInput& input,
                    TemplateURLService* template_url_service);
 
   // Returns true if at least one match was copied from the last result.
   bool HasCopiedMatches() const;
 
   // Vector-style accessors/operators.
   size_t size() const;
   bool empty() const;
@@ skipping 87 matching lines @@
   // user's local intranet contains site "foo", and the user types "foo", we
   // default to searching for "foo" when the user may have meant to navigate
   // there.  In cases like this, the default match will point to the "search for
   // 'foo'" result, and this will contain "http://foo/".
   GURL alternate_nav_url_;
 
   DISALLOW_COPY_AND_ASSIGN(AutocompleteResult);
 };
 
 #endif  // COMPONENTS_OMNIBOX_BROWSER_AUTOCOMPLETE_RESULT_H_