Fail gracefully when starting Chrome with an invalid kProfileDirectory.

chrome/browser/ui/browser_browsertest.cc

Index: chrome/browser/ui/browser_browsertest.cc
diff --git a/chrome/browser/ui/browser_browsertest.cc b/chrome/browser/ui/browser_browsertest.cc
index ac03700fe695c78442c32e3c893e94b3baee7642..c7d1fd9f725982e0b0fe3f4e4c7b218ead50b9c6 100644
--- a/chrome/browser/ui/browser_browsertest.cc
+++ b/chrome/browser/ui/browser_browsertest.cc
@@ -49,6 +49,7 @@
 #include "chrome/browser/ui/startup/startup_browser_creator_impl.h"
 #include "chrome/browser/ui/tabs/pinned_tab_codec.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/browser/ui/user_manager.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/manifest_handlers/app_launch_info.h"
 #include "chrome/common/pref_names.h"
@@ -2199,6 +2200,32 @@ class LaunchBrowserWithTrailingSlashDatadir : public BrowserTest {
   base::ScopedTempDir temp_dir_;
 };
 
+#if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
+// This test verifies that if Chrome is launched with an invalid
+// profile-directory argument, then the User Manager is shown instead.
+class LaunchBrowserWithInvalidProfileDirectory : public BrowserTest {
+ public:
+  LaunchBrowserWithInvalidProfileDirectory() {}
+
+  virtual void SetUpCommandLine(base::CommandLine* command_line) override {
+    command_line->AppendSwitch(switches::kEnableNewAvatarMenu);
+    command_line->AppendSwitchASCII(switches::kProfileDirectory,
+        "SomeOtherProfile");
+  }
+
+  base::ScopedTempDir temp_dir_;
+};
+
+IN_PROC_BROWSER_TEST_F(LaunchBrowserWithInvalidProfileDirectory,
+                       TestUserManagerShown) {
+  // No browser window should be open, and the User Manager should be showing.
+  EXPECT_FALSE(browser());
+  EXPECT_TRUE(UserManager::IsShowing());
+  // Hide the User Manager so that the test can die.
+  UserManager::Hide();
+}
+#endif  // !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
+
 IN_PROC_BROWSER_TEST_F(LaunchBrowserWithTrailingSlashDatadir,
                        TestTrailingSlashUserDataDir) {
   // Verify that the window is present.