Remove BackForwardClient, cleanup starting a history navigation

Source/core/frame/LocalDOMWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 65 matching lines @@
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/inspector/ScriptCallStack.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/loader/FrameLoadRequest.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/loader/MixedContentChecker.h"
 #include "core/loader/SinkDocument.h"
 #include "core/loader/appcache/ApplicationCache.h"
-#include "core/page/BackForwardClient.h"
 #include "core/page/Chrome.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/CreateWindow.h"
 #include "core/page/EventHandler.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/WindowFeatures.h"
 #include "core/page/WindowFocusAllowedIndicator.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/storage/Storage.h"
@@ skipping 882 matching lines @@
         if (!activeDocument)
             return;
 
         if (!activeDocument->canNavigate(*m_frame))
             return;
     }
 
     Settings* settings = m_frame->settings();
     bool allowScriptsToCloseWindows = settings && settings->allowScriptsToCloseWindows();
 
-    if (!(page->openedByDOM() || page->backForward().backForwardListCount() <= 1 || allowScriptsToCloseWindows)) {
+    if (!page->openedByDOM() && m_frame->loader().client()->backForwardLength() > 1 && !allowScriptsToCloseWindows) {
         frameConsole()->addMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel, "Scripts may close only the windows that were opened by it."));
         return;
     }
 
     if (!m_frame->loader().shouldClose())
         return;
 
     InspectorInstrumentation::willCloseWindow(context);
 
     page->chrome().closeWindowSoon();
@@ skipping 919 matching lines @@
     FrameDestructionObserver::trace(visitor);
 }
 
 v8::Handle<v8::Object> LocalDOMWindow::wrap(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
 {
     ASSERT_NOT_REACHED(); // LocalDOMWindow has [Custom=ToV8].
     return v8::Handle<v8::Object>();
 }
 
 } // namespace blink