Initialize chrome::DIR_USER_DATA early on for service processes, etc.

chrome/browser/user_data_dir_extractor.cc

 // Copyright (c) 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.
 
 #include "chrome/browser/user_data_dir_extractor.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
@@ skipping 76 matching lines @@
         IsStringUTF8(user_data_dir_string)) {
       user_data_dir = base::FilePath::FromUTF8Unsafe(user_data_dir_string);
     }
   }
 #endif
 #if defined(OS_MACOSX) || defined(OS_WIN)
   policy::path_parser::CheckUserDataDirPolicy(&user_data_dir);
 #endif
 
   // If the directory does not exist and cannot be created, prompt the user.
-  if (!user_data_dir.empty() &&
+  const bool specified_directory_was_invalid = !user_data_dir.empty() &&
       !PathService::OverrideAndCreateIfNeeded(chrome::DIR_USER_DATA,
-          user_data_dir, chrome::ProcessNeedsProfileDir(process_type))) {
+          user_data_dir, chrome::ProcessNeedsProfileDir(process_type));
+  if (specified_directory_was_invalid)
     ShowUserDataDirWarning(user_data_dir);
-  }
 
   // Getting the user data directory can fail if the directory isn't creatable.
   // ProcessSingleton needs a real user data directory on Mac/Linux, so it's
   // better to fail here than fail mysteriously elsewhere.
   CHECK(PathService::Get(chrome::DIR_USER_DATA, &user_data_dir))
       << "Must be able to get user data directory!";
+
+  // Append the fallback user data directory to the commandline. Otherwise,
+  // child or service processes will attempt to use the invalid directory.
+  if (specified_directory_was_invalid)
+    CommandLine::ForCurrentProcess()->AppendSwitchPath(switches::kUserDataDir,

[Vitaly Buka (NO REVIEWS), 2014/02/20 21:28:05]

actually you just did that 

+                                                       user_data_dir);
+
   return user_data_dir;
 }
 
 }  // namespace chrome