Add base::RunLoop and update ui_test_utils to use it to reduce flakiness

chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc

Index: chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
diff --git a/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc b/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
index 900581b4168f2bd56e2d9bd6a4ed64bfd9067f90..b86fbe41841f3c1a4e2c30f018d737b3e2093f46 100644
--- a/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
+++ b/chrome/browser/tab_contents/render_view_context_menu_browsertest_util.cc
@@ -11,20 +11,11 @@
 #include "content/public/browser/notification_service.h"
 
 ContextMenuNotificationObserver::ContextMenuNotificationObserver(
-    int command_to_execute,
-    int expected_notification)
-    : command_to_execute_(command_to_execute),
-      expected_notification_(expected_notification),
-      seen_expected_notification_(false) {
+    int command_to_execute)
+    : command_to_execute_(command_to_execute) {
   registrar_.Add(this,
                  chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN,
                  content::NotificationService::AllSources());
-  registrar_.Add(this,
-                 chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_CLOSED,
-                 content::NotificationService::AllSources());
-  registrar_.Add(this,
-                 expected_notification_,
-                 content::NotificationService::AllSources());
 }
 
 ContextMenuNotificationObserver::~ContextMenuNotificationObserver() {
@@ -34,11 +25,6 @@ void ContextMenuNotificationObserver::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-  if (type == expected_notification_) {
-    seen_expected_notification_ = true;
-    return;
-  }
-
   switch (type) {
     case chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN: {
       RenderViewContextMenu* context_menu =
@@ -49,17 +35,6 @@ void ContextMenuNotificationObserver::Observe(
                      base::Unretained(this), context_menu));
       break;
     }
-    case chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_CLOSED: {
-      // Aura is running a nested message loop for menus. That means that
-      // whatever the test running us is waiting for (e.g. a new tab to be
-      // added) happened while the menu message loop was running, so the
-      // message loop run by this test never quits.
-      if (seen_expected_notification_ &&
-          MessageLoop::current()->is_running()) {
-        MessageLoop::current()->QuitNow();
-      }
-      break;
-    }
 
     default:
       NOTREACHED();