Free temporary GPU and memory resources held by inactive or hidden 2D canvases

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 38 matching lines @@
 #include "core/page/PageGroup.h"
 #include "core/page/PageLifecycleNotifier.h"
 #include "core/page/PointerLockController.h"
 #include "core/frame/Settings.h"
 #include "core/page/ValidationMessageClient.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/TextAutosizer.h"
 #include "core/storage/StorageNamespace.h"
 #include "core/workers/SharedWorkerRepositoryClient.h"
+#include "platform/graphics/Canvas2DLayerManager.h"
 #include "platform/plugins/PluginData.h"
 #include "wtf/HashMap.h"
 #include "wtf/RefCountedLeakCounter.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/text/Base64.h"
 
 namespace WebCore {
 
 static HashSet<Page*>* allPages;
 
@@ skipping 390 matching lines @@
     if (visibilityState == WebCore::PageVisibilityStateHidden)
         setTimerAlignmentInterval(DOMTimer::hiddenPageAlignmentInterval());
     else
         setTimerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval());
 
     if (!isInitialState)
         lifecycleNotifier().notifyPageVisibilityChanged();
 
     if (!isInitialState && m_mainFrame)
         m_mainFrame->dispatchVisibilityStateChangeEvent();
+
+    if (visibilityState == WebCore::PageVisibilityStateHidden)
+        Canvas2DLayerManager::get().didHidePage();
 }
 
 PageVisibilityState Page::visibilityState() const
 {
     return m_visibilityState;
 }
 
 void Page::addMultisamplingChangedObserver(MultisamplingChangedObserver* observer)
 {
     m_multisamplingChangedObservers.add(observer);
@@ skipping 72 matching lines @@
     , backForwardClient(0)
     , spellCheckerClient(0)
 {
 }
 
 Page::PageClients::~PageClients()
 {
 }
 
 } // namespace WebCore