[Android] Add enhanced bookmark opt-in flag.

chrome/browser/bookmarks/enhanced_bookmarks_features.h

 // Copyright 2013 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_BOOKMARKS_ENHANCED_BOOKMARKS_FEATURES_H_
 #define CHROME_BROWSER_BOOKMARKS_ENHANCED_BOOKMARKS_FEATURES_H_
 
 #include <string>
 
 #include "extensions/common/extension.h"
 
 class PrefService;
+class Profile;
 
 // States for bookmark experiment. They are set by Chrome sync into
 // sync_driver::prefs::kEnhancedBookmarksExperimentEnabled user preference and
 // used for UMA reporting as well.
 enum BookmarksExperimentState {
   BOOKMARKS_EXPERIMENT_NONE,
   BOOKMARKS_EXPERIMENT_ENABLED,
   BOOKMARKS_EXPERIMENT_ENABLED_USER_OPT_OUT,
   BOOKMARKS_EXPERIMENT_ENABLED_FROM_FINCH,
   BOOKMARKS_EXPERIMENT_OPT_OUT_FROM_FINCH,
   BOOKMARKS_EXPERIMENT_ENABLED_FROM_FINCH_USER_SIGNEDIN,
   BOOKMARKS_EXPERIMENT_ENABLED_FROM_SYNC_UNKNOWN,
   BOOKMARKS_EXPERIMENT_ENUM_SIZE
 };
 
 // Returns true and sets |extension_id| if bookmarks experiment enabled
 //         false if no bookmark experiment or extension id is empty.
 bool GetBookmarksExperimentExtensionID(const PrefService* user_prefs,
                                        std::string* extension_id);
 
-// Updates bookmark experiment state based on information from Chrome sync
-// and Finch experiments.
+// Updates bookmark experiment state based on information from Chrome sync,
+// Finch experiments, and command line flag.
 void UpdateBookmarksExperimentState(
     PrefService* user_prefs,
     PrefService* local_state,
     bool user_signed_in,
     BookmarksExperimentState experiment_enabled_from_sync);
 
+// Same as UpdateBookmarksExperimentState, but the last argument with
+// BOOKMARKS_EXPERIMENT_ENABLED_FROM_SYNC_UNKNOWN.
+// Intended for performing initial configuration of bookmarks experiments
+// when the browser is first initialized.
+void InitBookmarksExperimentState(Profile* profile);
+
 // Sets flag to opt-in user into Finch experiment.
 void ForceFinchBookmarkExperimentIfNeeded(
     PrefService* local_state,
     BookmarksExperimentState bookmarks_experiment_state);
 
 // Returns true if enhanced bookmarks experiment is running.
 // Experiment could run by Chrome sync or by Finch.
 // Note that this doesn't necessarily mean that enhanced bookmarks
 // is enabled, e.g., user can opt out using a flag.
 bool IsEnhancedBookmarksExperimentEnabled();
 
 #if defined(OS_ANDROID)
 // Returns true if enhanced bookmark salient image prefetching is enabled.
 // This can be controlled by field trial.
 bool IsEnhancedBookmarkImageFetchingEnabled(const PrefService* user_prefs);
 
 // Returns true if enhanced bookmarks is enabled.
 bool IsEnhancedBookmarksEnabled(const PrefService* user_prefs);
 
 #endif
 
 // Returns true when flag enable-dom-distiller is set or enabled from Finch.
 bool IsEnableDomDistillerSet();
 
 // Returns true when flag enable-sync-articles is set or enabled from Finch.
 bool IsEnableSyncArticlesSet();
 
 #endif  // CHROME_BROWSER_BOOKMARKS_ENHANCED_BOOKMARKS_FEATURES_H_