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

chrome/browser/user_data_dir_extractor.cc

Index: chrome/browser/user_data_dir_extractor.cc
diff --git a/chrome/browser/user_data_dir_extractor.cc b/chrome/browser/user_data_dir_extractor.cc
index 3c7e9cbd1166f4fbd1194a6da026149f6993b2af..e2d17e96e79fe51f42d2d6e4e75158719351879e 100644
--- a/chrome/browser/user_data_dir_extractor.cc
+++ b/chrome/browser/user_data_dir_extractor.cc
@@ -94,17 +94,24 @@ base::FilePath GetUserDataDir(const content::MainFunctionParams& parameters) {
 #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;
 }