If possible, use the PathService instead of the --user-data-dir flag directly

chrome/service/cloud_print/cloud_print_proxy.cc

Index: chrome/service/cloud_print/cloud_print_proxy.cc
diff --git a/chrome/service/cloud_print/cloud_print_proxy.cc b/chrome/service/cloud_print/cloud_print_proxy.cc
index a98fecb4e5be00535e0fbadc089dfbf963b6ae31..39c38613ac4d378a5b370b5120f381f6ef9e46e8 100644
--- a/chrome/service/cloud_print/cloud_print_proxy.cc
+++ b/chrome/service/cloud_print/cloud_print_proxy.cc
@@ -11,6 +11,7 @@
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/values.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/cloud_print/cloud_print_constants.h"
 #include "chrome/common/cloud_print/cloud_print_proxy_info.h"
@@ -34,10 +35,8 @@ void LaunchBrowserProcessWithSwitch(const std::string& switch_string) {
   }
   base::CommandLine cmd_line(exe_path);
 
-  const base::CommandLine& process_command_line =

[grt (UTC plus 2), 2015/03/26 18:36:22]

i think this is okay as-is since the launched process will get the value from GP
if it is overridden there. i suggest:
  // Propagate an explicit --user-data-dir value if one was given. The new
  // browser process will pick up a policy override during initialization.

[noms (inactive), 2015/03/30 14:06:32]

Done.

-      *base::CommandLine::ForCurrentProcess();
-  base::FilePath user_data_dir =
-      process_command_line.GetSwitchValuePath(switches::kUserDataDir);
+  base::FilePath user_data_dir;
+  PathService::Get(chrome::DIR_USER_DATA, &user_data_dir);
   if (!user_data_dir.empty())
     cmd_line.AppendSwitchPath(switches::kUserDataDir, user_data_dir);
   cmd_line.AppendSwitch(switch_string);