Add MemoryPurgeController

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 377 matching lines @@
     if (visibilityState == PageVisibilityStateVisible)
         setTimerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval());
     else
         setTimerAlignmentInterval(DOMTimer::hiddenPageAlignmentInterval());
 
     if (!isInitialState)
         notifyPageVisibilityChanged();
 
     if (!isInitialState && m_mainFrame && m_mainFrame->isLocalFrame())
         deprecatedLocalMainFrame()->didChangeVisibilityState();
+
+    // TODO(bashi): Invoke this few seconds later.
+    if (visibilityState != PageVisibilityStateVisible)
+        m_memoryPurgeController.didBecomeInactive();
 }
 
 PageVisibilityState Page::visibilityState() const
 {
     return m_visibilityState;
 }
 
 bool Page::isCursorVisible() const
 {
     return m_isCursorVisible && settings().deviceSupportsMouse();
@@ skipping 186 matching lines @@
 {
 }
 
 Page::PageClients::~PageClients()
 {
 }
 
 template class CORE_TEMPLATE_EXPORT WillBeHeapSupplement<Page>;
 
 } // namespace blink