[Experiment] purge-and-suspend

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 4274 matching lines @@
     return canThrottleRendering() && lifecycle().throttlingAllowed();
 }
 
 bool FrameView::canThrottleRendering() const
 {
     if (!RuntimeEnabledFeatures::renderingPipelineThrottlingEnabled())
         return false;
     return m_subtreeThrottled || (m_hiddenForThrottling && m_crossOriginForThrottling);
 }
 
+void FrameView::purgeMemory()
+{
+    LayoutViewItem viewItem = layoutViewItem();
+    DCHECK(!viewItem.isNull());
+
+    PaintLayer* layer = viewItem.layer();
+    DCHECK(layer);
+    if (!layer->hasCompositedLayerMapping())
+        return;
+    GraphicsLayer* rootGraphicsLayer = layer->compositedLayerMapping()->mainGraphicsLayer();
+    if (!rootGraphicsLayer->drawsContent())
+        return;
+    rootGraphicsLayer->getPaintController().invalidateAll();

[esprehn, 2016/08/05 23:00:58]

This is only the main graphics layer, what about all of the other ones? Are we
sure this does the right thing?

[tasak, 2016/08/08 04:47:36]

I see. I would like to traverse all children and to invoke their
paintController's "invalidateAll()".

+}
+
 } // namespace blink