Unload the ScopedGaiaAuthExtension asynchronously.

chrome/browser/ui/cocoa/bookmarks/bookmark_sync_promo_controller_unittest.mm

Index: chrome/browser/ui/cocoa/bookmarks/bookmark_sync_promo_controller_unittest.mm
diff --git a/chrome/browser/ui/cocoa/bookmarks/bookmark_sync_promo_controller_unittest.mm b/chrome/browser/ui/cocoa/bookmarks/bookmark_sync_promo_controller_unittest.mm
index 90160c16f5ebb65a72dbc774ae73b6f724ca801f..0f26351d39a42a47629e433f1dad0a4f040f1318 100644
--- a/chrome/browser/ui/cocoa/bookmarks/bookmark_sync_promo_controller_unittest.mm
+++ b/chrome/browser/ui/cocoa/bookmarks/bookmark_sync_promo_controller_unittest.mm
@@ -43,6 +43,11 @@ TEST_F(BookmarkSyncPromoControllerTest, SignInLink) {
   // A new tab should have been opened.
   int tab_count = browser()->tab_strip_model()->count();
   EXPECT_EQ(starting_tab_count + 1, tab_count);
+
+  // Close the tab, so that the gaia auth extension is unloaded correctly.
+  // Otherwise the test can crash if the profile is deleted before the extension
+  // is unloaded.
+  browser()->tab_strip_model()->CloseAllTabs();
 }
 
 }  // namespace