Reland "Streamline frame detach"

Source/core/page/Page.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All Rights Reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 110 matching lines @@
     , m_focusController(FocusController::create(this))
     , m_contextMenuController(ContextMenuController::create(this, pageClients.contextMenuClient))
     , m_inspectorController(InspectorController::create(this, pageClients.inspectorClient))
     , m_pointerLockController(PointerLockController::create(this))
     , m_undoStack(UndoStack::create())
     , m_mainFrame(nullptr)
     , m_backForwardClient(pageClients.backForwardClient)
     , m_editorClient(pageClients.editorClient)
     , m_spellCheckerClient(pageClients.spellCheckerClient)
     , m_storageClient(pageClients.storageClient)
-    , m_subframeCount(0)
     , m_openedByDOM(false)
     , m_tabKeyCyclesThroughElements(true)
     , m_defersLoading(false)
     , m_deviceScaleFactor(1)
     , m_timerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval())
     , m_visibilityState(PageVisibilityStateVisible)
     , m_isCursorVisible(true)
 #if ENABLE(ASSERT)
     , m_isPainting(false)
 #endif
@@ skipping 292 matching lines @@
         if (frame->isLocalFrame() && toLocalFrame(frame)->document())
             toLocalFrame(frame)->document()->didChangeTimerAlignmentInterval();
     }
 }
 
 double Page::timerAlignmentInterval() const
 {
     return m_timerAlignmentInterval;
 }
 
-#if ENABLE(ASSERT)
-void Page::checkSubframeCountConsistency() const
-{
-    ASSERT(m_subframeCount >= 0);
-
-    int subframeCount = 0;
-    for (Frame* frame = mainFrame(); frame; frame = frame->tree().traverseNext())
-        ++subframeCount;
-
-    ASSERT(m_subframeCount + 1 == subframeCount);
-}
-#endif
-
 void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitialState)
 {
     if (m_visibilityState == visibilityState)
         return;
     m_visibilityState = visibilityState;
 
     if (visibilityState == blink::PageVisibilityStateVisible)
         setTimerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval());
     else
         setTimerAlignmentInterval(DOMTimer::hiddenPageAlignmentInterval());
@@ skipping 203 matching lines @@
     , spellCheckerClient(0)
     , storageClient(0)
 {
 }
 
 Page::PageClients::~PageClients()
 {
 }
 
 } // namespace blink