Fail gracefully when starting Chrome with an invalid kProfileDirectory.

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index c250470a47a87a8c9aeb8299b86069b1bfc4c714..637e4c31303200cac61ae70809f0a06ad630da50 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -353,13 +353,22 @@ Profile* CreatePrimaryProfile(const content::MainFunctionParams& parameters,
 #else
   base::FilePath profile_path =
       GetStartupProfilePath(user_data_dir, parsed_command_line);
+  const ProfileInfoCache& cache =
+      g_browser_process->profile_manager()->GetProfileInfoCache();
+
+  // If we are trying to load a profile that has been deleted (for example from
+  // an old shortcut, or using an incorrect kProfileDirectory argument), set
+  // the active profile to Guest to force showing the User Manager.
+  size_t profile_index = cache.GetIndexOfProfileWithPath(profile_path);
+  if (profile_index == std::string::npos)
+    profile_path = ProfileManager::GetGuestProfilePath();
 
   // Without NewAvatarMenu, replace guest with any existing profile.
   if (!switches::IsNewAvatarMenu() &&
       profile_path == ProfileManager::GetGuestProfilePath()) {
-    profile_path = g_browser_process->profile_manager()->GetProfileInfoCache().
-        GetPathOfProfileAtIndex(0);
+    profile_path = cache.GetPathOfProfileAtIndex(0);
   }
+
   profile = g_browser_process->profile_manager()->GetProfile(
       profile_path);
 
@@ -370,12 +379,7 @@ Profile* CreatePrimaryProfile(const content::MainFunctionParams& parameters,
   if (switches::IsNewProfileManagement() &&
       profile &&
       !profile->IsGuestSession()) {
-    ProfileInfoCache& cache =
-        g_browser_process->profile_manager()->GetProfileInfoCache();
-    size_t profile_index = cache.GetIndexOfProfileWithPath(profile_path);
-
-    if (profile_index != std::string::npos &&
-        cache.ProfileIsSigninRequiredAtIndex(profile_index)) {
+    if (cache.ProfileIsSigninRequiredAtIndex(profile_index)) {
       profile = g_browser_process->profile_manager()->GetProfile(
           ProfileManager::GetGuestProfilePath());
     }