Raise the loading priority of in-viewport images.

Source/core/rendering/RenderBlock.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * 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.
@@ skipping 377 matching lines @@
     // inline-block elements paint all phases atomically. This function ensures that. Certain other elements
     // (grid items, flex items) require this behavior as well, and this function exists as a helper for them.
     // It is expected that the caller will call this function independent of the value of paintInfo.phase.
     static void paintAsInlineBlock(RenderObject*, PaintInfo&, const LayoutPoint&);
 protected:
     virtual void willBeDestroyed();
 
     void dirtyForLayoutFromPercentageHeightDescendants(SubtreeLayoutScope&);
 
     virtual void layout();
+    virtual void didLayout(ResourceLoadPriorityOptimizer&);
+    virtual void didScroll(ResourceLoadPriorityOptimizer&);
+    void updateStyleImageLoadingPriorities(ResourceLoadPriorityOptimizer&);
 
     void layoutPositionedObjects(bool relayoutChildren, bool fixedPositionObjectsOnly = false);
     void markFixedPositionObjectForLayoutIfNeeded(RenderObject* child, SubtreeLayoutScope&);
 
     LayoutUnit marginIntrinsicLogicalWidthForChild(RenderBox* child) const;
 
     virtual bool supportsPartialLayout() const OVERRIDE { return true; };
 
     virtual void paint(PaintInfo&, const LayoutPoint&);
     virtual void paintObject(PaintInfo&, const LayoutPoint&);
@@ skipping 309 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of RenderBlock and into RenderBlockFlow.
     friend class RenderBlockFlow;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBlock, isRenderBlock());
 
 } // namespace WebCore
 
 #endif // RenderBlock_h