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

chrome/common/switch_utils.h

 // Copyright (c) 2010 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_COMMON_SWITCH_UTILS_H_
 #define CHROME_COMMON_SWITCH_UTILS_H_
 
 #include <map>
 #include <string>
 
 #include "base/command_line.h"
 
+namespace base {
+class FilePath;
+}
+
 namespace switches {
 
 // Remove the keys that we shouldn't pass through during restart.
 void RemoveSwitchesForAutostart(
     std::map<std::string, CommandLine::StringType>* switches);
 
+// Initializes the user data dir. Must be called before InitializeLocalState().
+void InitializeUserDataDir();

[Vitaly Buka (NO REVIEWS), 2014/02/21 23:11:33]

How about adding bool IsUserDataDirInitialized() initialized

and DCHECK(IsUserDataDirInitialized)in 

chrome_paths.cc:158

switch (key) {
    case chrome::DIR_USER_DATA:
      DCHECK(IsUserDataDirInitialized());
      if (!GetDefaultUserDataDirectory(&cur)) {

[msw, 2014/02/21 23:38:30]

Sadly, I intended this functionality to live in chrome_paths.cc altogether, but
that's part of the common_constants target, which this code depends upon. So
this code can't live there or be called from there without creating a circular
dependency. Your idea could be implemented by setting a flag in chrome_paths.cc
from InitializeUserDataDir, so I've done that, please take a look.

+
+// Returns the originally specified user data dir if it was invalid.
+const base::FilePath& GetInvalidSpecifiedUserDataDir();
+
 }  // namespace switches
 
 #endif  // CHROME_COMMON_SWITCH_UTILS_H_