Remove BackForwardClient, cleanup starting a history navigation

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. 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.
@@ skipping 46 matching lines @@
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/html/HTMLFrameSetElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/inspector/InspectorController.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/page/AutoscrollController.h"
-#include "core/page/BackForwardClient.h"
 #include "core/page/Chrome.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/DragController.h"
 #include "core/page/DragState.h"
 #include "core/page/EditorClient.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/SpatialNavigation.h"
 #include "core/page/TouchAdjustment.h"
@@ skipping 3301 matching lines @@
 
 void EventHandler::defaultBackspaceEventHandler(KeyboardEvent* event)
 {
     ASSERT(event->type() == EventTypeNames::keydown);
 
     if (event->ctrlKey() || event->metaKey() || event->altKey())
         return;
 
     if (!m_frame->editor().behavior().shouldNavigateBackOnBackspace())
         return;
-
-    Page* page = m_frame->page();
-    if (!page || !page->mainFrame()->isLocalFrame())
-        return;
-    bool handledEvent = page->deprecatedLocalMainFrame()->loader().client()->navigateBackForward(event->shiftKey() ? 1 : -1);
+    bool handledEvent = m_frame->loader().client()->navigateBackForward(event->shiftKey() ? 1 : -1);
     if (handledEvent)
         event->setDefaultHandled();
 }
 
 void EventHandler::defaultArrowEventHandler(FocusType focusType, KeyboardEvent* event)
 {
     ASSERT(event->type() == EventTypeNames::keydown);
 
     if (event->ctrlKey() || event->metaKey() || event->shiftKey())
         return;
@@ skipping 481 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink