Avoid loading the last used browser profile in app_controller_mac when it's not needed.

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 e1b0625e3d219a3781fe95dfcc82e6ac30ae8321..8496d2bc1e8900881ddaf0ef75b4e07f6858819d 100644
--- a/chrome/browser/ui/startup/startup_browser_creator.h
+++ b/chrome/browser/ui/startup/startup_browser_creator.h
@@ -170,4 +170,9 @@ class StartupBrowserCreator {
 // after the unclean exit.
 bool HasPendingUncleanExit(Profile* profile);
 
+// Returns the path that contains the profile that should be loaded on process
+// startup.
+base::FilePath GetStartupProfilePath(const base::FilePath& user_data_dir,
+                                     const CommandLine& command_line);
+
 #endif  // CHROME_BROWSER_UI_STARTUP_STARTUP_BROWSER_CREATOR_H_