Skip a first-run import on Mac when there is nothing left to import.

chrome/browser/first_run/first_run.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_FIRST_RUN_FIRST_RUN_H_
 #define CHROME_BROWSER_FIRST_RUN_FIRST_RUN_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 117 matching lines @@
 
 // Imports bookmarks and/or browser items (depending on platform support)
 // in this process. This function is paired with first_run::ImportSettings().
 // This function might or might not show a visible UI depending on the
 // cmdline parameters.
 int ImportNow(Profile* profile, const CommandLine& cmdline);
 
 // Returns the path for the master preferences file.
 FilePath MasterPrefsPath();
 
+// Set a master preferences file path that overrides platform defaults.
+void SetMasterPrefsPathForTesting(const FilePath& master_prefs);
+
 // The master preferences is a JSON file with the same entries as the
 // 'Default\Preferences' file. This function locates this file from a standard
 // location and processes it so it becomes the default preferences in the
 // profile pointed to by |user_data_dir|. After processing the file, the
 // function returns a value from the ProcessMasterPreferencesResult enum,
 // indicating whether the first run flow should be shown, skipped, or whether
 // the browser should exit.
 //
 // This function destroys any existing prefs file and it is meant to be
 // invoked only on first run.
@@ skipping 22 matching lines @@
                        const content::NotificationDetails& details) OVERRIDE;
 
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(FirstRunBubbleLauncher);
 };
 
 }  // namespace first_run
 
 #endif  // CHROME_BROWSER_FIRST_RUN_FIRST_RUN_H_