The User Manager should be backed by a special profile, not the guest one.

chrome/common/chrome_constants.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.
 
 // A handful of resource-like constants related to the Chrome application.
 
 #ifndef CHROME_COMMON_CHROME_CONSTANTS_H_
 #define CHROME_COMMON_CHROME_CONSTANTS_H_
 
 #include "base/files/file_path.h"
@@ skipping 31 matching lines @@
 #endif  // OS_MACOSX
 #if defined(OS_WIN)
 extern const base::FilePath::CharType kMetroDriverDll[];
 extern const wchar_t kStatusTrayWindowClass[];
 #endif  // defined(OS_WIN)
 extern const wchar_t kCrashReportLog[];
 extern const wchar_t kTestingInterfaceDLL[];
 extern const char    kInitialProfile[];
 extern const char    kMultiProfileDirPrefix[];
 extern const base::FilePath::CharType kGuestProfileDir[];
+extern const base::FilePath::CharType kUserManagerProfileDir[];

[Nico, 2014/04/16 18:03:16]

Any reason these aren't char like kInitialProfile? (With AppendASCII() on
FilePath, it shouldn't make much of a difference at the using site?)

[noms (inactive), 2014/04/16 18:36:03]

Done.
On 2014/04/16 18:03:16, Nico wrote:

 extern const wchar_t kBrowserResourcesDll[];
 
 // filenames
 #if defined(OS_ANDROID)
 extern const base::FilePath::CharType kAndroidCacheFilename[];
 #endif
 extern const base::FilePath::CharType kArchivedHistoryFilename[];
 extern const base::FilePath::CharType kCacheDirname[];
 extern const base::FilePath::CharType kCookieFilename[];
 extern const base::FilePath::CharType kCRLSetFilename[];
@@ skipping 97 matching lines @@
 extern const char kApplicationClientIDStringForAVScanning[];
 
 #if defined(OS_ANDROID)
 // The largest reasonable length we'd assume for a meta tag attribute.
 extern const size_t kMaxMetaTagAttributeLength;
 #endif
 
 }  // namespace chrome
 
 #endif  // CHROME_COMMON_CHROME_CONSTANTS_H_