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

chrome/browser/automation/automation_provider_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/automation/automation_provider.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/debug/trace_event.h"
 #include "base/json/json_reader.h"
+#include "base/run_loop.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/automation/automation_browser_tracker.h"
 #include "chrome/browser/automation/automation_tab_tracker.h"
 #include "chrome/browser/automation/automation_window_tracker.h"
 #include "chrome/browser/external_tab/external_tab_container.h"
 #include "chrome/browser/printing/print_view_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/restore_tab_helper.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/tab_contents/tab_contents.h"
 #include "chrome/common/automation_messages.h"
 #include "chrome/common/render_messages.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/page_zoom.h"
 #include "ui/base/keycodes/keyboard_codes.h"
 #include "ui/ui_controls/ui_controls.h"
 #include "ui/views/focus/accelerator_handler.h"
 #include "ui/views/widget/root_view.h"
 
 using content::NavigationController;
 using content::RenderViewHost;
 using content::WebContents;
 
 namespace {
 
+// Allow some pending tasks up to |num_deferrals| generations to complete.
+void DeferredQuitRunLoop(const base::Closure& quit_task,
+                         int num_quit_deferrals) {
+  if (num_quit_deferrals <= 0) {
+    quit_task.Run();
+  } else {
+    MessageLoop::current()->PostTask(FROM_HERE,
+        base::Bind(&DeferredQuitRunLoop, quit_task, num_quit_deferrals - 1));
+  }
+}
+
 // This callback just adds another callback to the event queue. This is useful
 // if you want to ensure that any callbacks added to the event queue after this
 // one have already been processed by the time |callback| is run.
 void InvokeCallbackLater(const base::Closure& callback) {
   MessageLoop::current()->PostTask(FROM_HERE, callback);
 }
 
 void MoveMouse(const POINT& point) {
   SetCursorPos(point.x, point.y);
 
@@ skipping 83 matching lines @@
       SendMessage(top_level_hwnd, WM_MOUSEMOVE, wparam_flags,
                   MAKELPARAM(drag_path[i].x(), drag_path[i].y()));
     }
     POINT end = drag_path[drag_path.size() - 1].ToPOINT();
     MapWindowPoints(top_level_hwnd, HWND_DESKTOP, &end, 1);
     MoveMouse(end);
 
     if (press_escape_en_route) {
       // Press Escape, making sure we wait until chrome processes the escape.
       // TODO(phajdan.jr): make this use ui_test_utils::SendKeyPressSync.
+      views::AcceleratorHandler handler;
+      base::RunLoop run_loop(&handler);
+      // Number of times to repost Quit task to allow pending tasks to complete.
+      // See kNumQuitDeferrals in ui_test_utils.cc for explanation.
+      int num_quit_deferrals = 10;
       ui_controls::SendKeyPressNotifyWhenDone(
           window, ui::VKEY_ESCAPE,
           ((flags & ui::EF_CONTROL_DOWN) ==
            ui::EF_CONTROL_DOWN),
           ((flags & ui::EF_SHIFT_DOWN) ==
            ui::EF_SHIFT_DOWN),
           ((flags & ui::EF_ALT_DOWN) == ui::EF_ALT_DOWN),
           false,
-          MessageLoop::QuitClosure());
+          base::Bind(&DeferredQuitRunLoop, run_loop.QuitClosure(),
+                     num_quit_deferrals));
       MessageLoopForUI* loop = MessageLoopForUI::current();
-      views::AcceleratorHandler handler;
       MessageLoop::ScopedNestableTaskAllower allow(loop);
-      loop->RunWithDispatcher(&handler);
+      run_loop.Run();
     }
     SendMessage(top_level_hwnd, up_message, wparam_flags,
                 MAKELPARAM(end.x, end.y));
 
     MessageLoop::current()->PostTask(
         FROM_HERE, base::Bind(
             &InvokeCallbackLater,
             base::Bind(&WindowDragResponseCallback, this, reply_message)));
   } else {
     AutomationMsg_WindowDrag::WriteReplyParams(reply_message, false);
@@ skipping 236 matching lines @@
 void AutomationProvider::OnSetZoomLevel(int handle, int zoom_level) {
   if (tab_tracker_->ContainsHandle(handle)) {
     NavigationController* tab = tab_tracker_->GetResource(handle);
     if (tab->GetWebContents() && tab->GetWebContents()->GetRenderViewHost()) {
       RenderViewHost* host = tab->GetWebContents()->GetRenderViewHost();
       content::PageZoom zoom = static_cast<content::PageZoom>(zoom_level);
       host->Zoom(zoom);
     }
   }
 }