Revert of Revert "Revert of Reland: Switch WindowedNotificationObserver to use base::RunLoop.

chrome/browser/ui/views/constrained_window_views_browsertest.cc

Index: chrome/browser/ui/views/constrained_window_views_browsertest.cc
diff --git a/chrome/browser/ui/views/constrained_window_views_browsertest.cc b/chrome/browser/ui/views/constrained_window_views_browsertest.cc
index a78c73c2d421e1ba480c521a3f8d582a26a2b78f..5db441f1a9143d94846528364e2cb8fe89a793ac 100644
--- a/chrome/browser/ui/views/constrained_window_views_browsertest.cc
+++ b/chrome/browser/ui/views/constrained_window_views_browsertest.cc
@@ -211,12 +211,6 @@
   content::RunAllPendingInMessageLoop();
   content::WaitForLoadStop(web_contents);
 
-  // When Widget::Close is called, a task is posted that will destroy the
-  // widget. Here the widget is closed when the navigation commits. Load stop
-  // may occur right after the commit, before the widget is destroyed.
-  // Execute pending tasks to account for this.
-  base::RunLoop().RunUntilIdle();
-
   EXPECT_EQ(nullptr, dialog->GetWidget());
   EXPECT_EQ(original_url, web_contents->GetURL());
 }