Support "await a stable state" and "provide a stable state"

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 119 matching lines @@
 #include "core/html/HTMLHeadElement.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "core/html/HTMLImport.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLLinkElement.h"
 #include "core/html/HTMLNameCollection.h"
 #include "core/html/HTMLScriptElement.h"
 #include "core/html/HTMLStyleElement.h"
 #include "core/html/HTMLTitleElement.h"
 #include "core/html/PluginDocument.h"
+#include "core/html/StableState.h"
 #include "core/html/forms/FormController.h"
 #include "core/html/parser/HTMLDocumentParser.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/html/parser/NestingLevelIncrementer.h"
 #include "core/html/parser/TextResourceDecoder.h"
 #include "core/inspector/InspectorCounters.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/ScriptCallStack.h"
 #include "core/loader/CookieJar.h"
 #include "core/loader/DocumentLoader.h"
@@ skipping 2359 matching lines @@
     if (!beforeUnloadEvent->defaultPrevented())
         defaultEventHandler(beforeUnloadEvent.get());
     if (beforeUnloadEvent->returnValue().isNull())
         return true;
 
     if (didAllowNavigation) {
         addConsoleMessage(JSMessageSource, ErrorMessageLevel, "Blocked attempt to show multiple 'beforeunload' confirmation panels for a single navigation.");
         return true;
     }
 
+    // http://whatwg.org/html#pause

[tkent, 2014/02/06 04:27:46]

This comment doesn't explain why we need to pause here.

+    StableState::provide();
+
     String text = beforeUnloadEvent->returnValue();
     if (chrome.runBeforeUnloadConfirmPanel(text, m_frame)) {
         didAllowNavigation = true;
         return true;
     }
     return false;
 }
 
 void Document::dispatchUnloadEvents()
 {
@@ skipping 2897 matching lines @@
 void Document::defaultEventHandler(Event* event)
 {
     if (frame() && frame()->remotePlatformLayer()) {
         frame()->chromeClient().forwardInputEvent(this, event);
         return;
     }
     Node::defaultEventHandler(event);
 }
 
 } // namespace WebCore