Use OffTheRecord version when using Guest profiles to handle commands.

chrome/browser/app_controller_mac.mm

Index: chrome/browser/app_controller_mac.mm
diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index 70b0707c5dea2c852de1dd84aee4dbdbcca41080..f3227efd01216acbde28a52d91768bb025f2acef 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -955,7 +955,7 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
 // check, otherwise it should have been disabled in the UI in
 // |-validateUserInterfaceItem:|.
 - (void)commandDispatch:(id)sender {
-  Profile* lastProfile = [self lastProfile];
+  Profile* lastProfile = [self safeLastProfileForNewWindows];
 
   // Handle the case where we're dispatching a command from a sender that's in a
   // browser window. This means that the command came from a background window
@@ -1290,6 +1290,16 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
       *CommandLine::ForCurrentProcess()));
 }
 
+- (Profile*)safeLastProfileForNewWindows {
+  Profile* profile = [self lastProfile];
+
+  // Guest sessions must always be OffTheRecord. Use that when opening windows.
+  if (profile->IsGuestSession())
+    return profile->GetOffTheRecordProfile();
+
+  return profile;
+}
+
 // Various methods to open URLs that we get in a native fashion. We use
 // StartupBrowserCreator here because on the other platforms, URLs to open come
 // through the ProcessSingleton, and it calls StartupBrowserCreator. It's best
@@ -1353,7 +1363,7 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
     chrome::ShowSettings(browser);
   } else {
     // No browser window, so create one for the options tab.
-    chrome::OpenOptionsWindow([self lastProfile]);
+    chrome::OpenOptionsWindow([self safeLastProfileForNewWindows]);
   }
 }
 
@@ -1362,7 +1372,7 @@ class AppControllerProfileObserver : public ProfileInfoCacheObserver {
     chrome::ShowAboutChrome(browser);
   } else {
     // No browser window, so create one for the about tab.
-    chrome::OpenAboutWindow([self lastProfile]);
+    chrome::OpenAboutWindow([self safeLastProfileForNewWindows]);
   }
 }