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

chrome/browser/extensions/chrome_extension_test_notification_observer.cc

Index: chrome/browser/extensions/chrome_extension_test_notification_observer.cc
diff --git a/chrome/browser/extensions/chrome_extension_test_notification_observer.cc b/chrome/browser/extensions/chrome_extension_test_notification_observer.cc
index cf28829595ad10711b0fe7db184fd3163cc7cbfa..7a34f44879910aad22c8a6e5cea6878e09da2dbe 100644
--- a/chrome/browser/extensions/chrome_extension_test_notification_observer.cc
+++ b/chrome/browser/extensions/chrome_extension_test_notification_observer.cc
@@ -11,7 +11,6 @@
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/web_contents.h"
-#include "content/public/test/test_utils.h"
 #include "extensions/browser/notification_types.h"
 #include "extensions/browser/process_manager.h"
 #include "extensions/common/extension.h"
@@ -81,10 +80,6 @@
 }
 
 bool ChromeExtensionTestNotificationObserver::WaitForExtensionViewsToLoad() {
-  // Some views might be not created yet. This call may become insufficient if
-  // e.g. implementation of ExtensionHostQueue changes.
-  content::RunAllPendingInMessageLoop();
-
   ProcessManager* manager = ProcessManager::Get(GetBrowserContext());
   NotificationSet notification_set;
   notification_set.Add(content::NOTIFICATION_WEB_CONTENTS_DESTROYED);