Fix Launcher crash in ChromeOS guest mode.

chrome/browser/ui/app_list/app_list_view_delegate.cc

Index: chrome/browser/ui/app_list/app_list_view_delegate.cc
diff --git a/chrome/browser/ui/app_list/app_list_view_delegate.cc b/chrome/browser/ui/app_list/app_list_view_delegate.cc
index c40337660723557465cafd412a572d1a3c39a0f2..21824a02f1ac781a16208140d059548bcf56a26d 100644
--- a/chrome/browser/ui/app_list/app_list_view_delegate.cc
+++ b/chrome/browser/ui/app_list/app_list_view_delegate.cc
@@ -285,6 +285,13 @@ void AppListViewDelegate::SetProfile(Profile* new_profile) {
     return;
   }
 
+  // If we are in guest mode, the new profile should be an incognito profile.
+  // Otherwise, this may later hit a check (same condition as this one) in
+  // Browser::Browser when opening links in a browser window (see
+  // http://crbug.com/460437).
+  DCHECK(!profile_->IsGuestSession() || profile_->IsOffTheRecord())
+      << "Guest mode must use incognito profile";
+
   // TODO(vadimt): Remove ScopedTracker below once crbug.com/431326 is fixed.
   tracked_objects::ScopedTracker tracking_profile3(
       FROM_HERE_WITH_EXPLICIT_FUNCTION(