Add fallback behavior if the last used profile cannot initialize

chrome/browser/ui/startup/startup_browser_creator.h

Index: chrome/browser/ui/startup/startup_browser_creator.h
diff --git a/chrome/browser/ui/startup/startup_browser_creator.h b/chrome/browser/ui/startup/startup_browser_creator.h
index f2e3c0a5fd757609b5df07e3960161ba5350888d..aeb778a9b52710a830abddf3bfce868969ae41b8 100644
--- a/chrome/browser/ui/startup/startup_browser_creator.h
+++ b/chrome/browser/ui/startup/startup_browser_creator.h
@@ -179,4 +179,19 @@ bool HasPendingUncleanExit(Profile* profile);
 base::FilePath GetStartupProfilePath(const base::FilePath& user_data_dir,
                                      const base::CommandLine& command_line);
 
+#if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
+// Returns the profile that should be loaded on process startup. This is either
+// the profile return by GetStartupProfilePath, or the user manager if the above
+// profile is signed out. Returns null if this profile cannot be opened. In case
+// of user manager, returns null if either the guest profile and the system
+// profile cannot be opened.
+Profile* GetStartupProfile(const base::FilePath& user_data_dir,
+                           const base::CommandLine& command_line);
+
+// Returns the a fallback profile that should be loaded on process startup.
+// Possible to return null, which means no profile (including user manager) can
+// be opened.
+Profile* GetFallbackStartupProfile();
+#endif  // !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
+
 #endif  // CHROME_BROWSER_UI_STARTUP_STARTUP_BROWSER_CREATOR_H_