Adding show profile switcher field trial.

chrome/browser/profiles/profile_manager.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.
 
 // This class keeps track of the currently-active profiles in the runtime.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_
 
 #include <list>
@@ skipping 184 matching lines @@
   // profile specfic desktop shortcuts.
   ProfileShortcutManager* profile_shortcut_manager();
 
   // Schedules the profile at the given path to be deleted on shutdown.
   void ScheduleProfileForDeletion(const FilePath& profile_dir,
                                   chrome::HostDesktopType desktop_type);
 
   // Checks if multiple profiles is enabled.
   static bool IsMultipleProfilesEnabled();
 
+  // Force IsMultipleProfilesEnabled to return a given value. For testing
+  // purposes.
+  static void ForceMultipleProfilesForTests(bool forcedValue);
+
+  // Lets IsMultipleProfilesEnabled behave in a normal, unforced way.
+  static void UnforceMultipleProfilesForTests();
+
   // Autoloads profiles if they are running background apps.
   void AutoloadProfiles();
 
   // Register and add testing profile to the ProfileManager. Use ONLY in tests.
   // This allows the creation of Profiles outside of the standard creation path
   // for testing. If |addToCache|, add to ProfileInfoCache as well.
   void RegisterTestingProfile(Profile* profile, bool addToCache);
 
   const FilePath& user_data_dir() const { return user_data_dir_; }
 
@@ skipping 127 matching lines @@
   BrowserListObserver browser_list_observer_;
 #endif  // !defined(OS_ANDROID) && !defined(OS_IOS)
 
   // For keeping track of the last active profiles.
   std::map<Profile*, int> browser_counts_;
   // On startup we launch the active profiles in the order they became active
   // during the last run. This is why they are kept in a list, not in a set.
   std::vector<Profile*> active_profiles_;
   bool closing_all_browsers_;
 
+  // For forcing IsMultiProfilesEnabled to the value of
+  // multiple_profiles_forced_value_. Used for testing.
+  static bool is_multiple_profiles_forced_;

[sail, 2013/01/31 17:15:23]

maybe use an enum instead of 2 bools, something like
  default
  force_on
  force_off

[jwd, 2013/01/31 19:26:11]

Done. Kept the api the same though.

+
+  // The value returned by IsMultiProfilesEnabled when it's been forced. Used
+  // for testing.
+  static bool multiple_profiles_forced_value_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileManager);
 };
 
 // Same as the ProfileManager, but doesn't initialize some services of the
 // profile. This one is useful in unittests.
 class ProfileManagerWithoutInit : public ProfileManager {
  public:
   explicit ProfileManagerWithoutInit(const FilePath& user_data_dir);
 
  protected:
   virtual void DoFinalInitForServices(Profile*, bool) OVERRIDE {}
   virtual void DoFinalInitLogging(Profile*) OVERRIDE {}
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_