When enabling new profile management programmatically, make sure to set the

chrome/browser/profiles/profile_window.cc

Index: chrome/browser/profiles/profile_window.cc
diff --git a/chrome/browser/profiles/profile_window.cc b/chrome/browser/profiles/profile_window.cc
index 1b52daa5a9485c5310493add0be105b251a5639e..6fd2ea23278c2e8ffbde0c6684b86603afcdd028 100644
--- a/chrome/browser/profiles/profile_window.cc
+++ b/chrome/browser/profiles/profile_window.cc
@@ -321,11 +321,26 @@ void EnableNewProfileManagementPreview(Profile* profile) {
 #if defined(OS_ANDROID)
   NOTREACHED();
 #else
+  // TODO(rogerta): instead of setting experiment flags and command line
+  // args, we should set a profile preference.
+  const about_flags::Experiment experiment = {
+      kNewProfileManagementExperimentInternalName,
+      0,  // string id for title of experiment
+      0,  // string id for description of experiment

[noms (inactive), 2014/06/20 14:44:19]

optional nit: Do these have to be capitalized and end in a period? (I don't
know)

+      0,  // supported platforms
+      about_flags::Experiment::ENABLE_DISABLE_VALUE,
+      switches::kEnableNewProfileManagement,
+      "",  // not used with ENABLE_DISABLE_VALUE type
+      switches::kDisableNewProfileManagement,
+      "",  // not used with ENABLE_DISABLE_VALUE type
+      NULL,  // not used with ENABLE_DISABLE_VALUE type
+      3
+  };
   about_flags::PrefServiceFlagsStorage flags_storage(
       g_browser_process->local_state());
   about_flags::SetExperimentEnabled(
       &flags_storage,
-      kNewProfileManagementExperimentInternalName,
+      experiment.NameForChoice(1),
       true);
 
   switches::EnableNewProfileManagementForTesting(