Adapt and reland old position sticky implementation

Source/platform/graphics/GraphicsLayer.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 319 matching lines @@
 
     GraphicsLayer* m_maskLayer; // Reference to mask layer. We don't own this.
     GraphicsLayer* m_contentsClippingMaskLayer; // Reference to clipping mask layer. We don't own this.
 
     GraphicsLayer* m_replicaLayer; // A layer that replicates this layer. We only allow one, for now.
                                    // The replica is not parented; this is the primary reference to it.
     GraphicsLayer* m_replicatedLayer; // For a replica layer, a reference to the original layer.
     FloatPoint m_replicatedLayerPosition; // For a replica layer, the position of the replica.
 
     IntRect m_contentsRect;
+    IntRect m_containingRect;
 
     int m_paintCount;
 
     OwnPtr<WebContentLayer> m_layer;
     OwnPtr<WebImageLayer> m_imageLayer;
     WebLayer* m_contentsLayer;
     // We don't have ownership of m_contentsLayer, but we do want to know if a given layer is the
     // same as our current layer in setContentsTo(). Since m_contentsLayer may be deleted at this point,
     // we stash an ID away when we know m_contentsLayer is alive and use that for comparisons from that point
     // on.
@@ skipping 11 matching lines @@
 };
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the blink namespace for ease of invocation from gdb.
 void PLATFORM_EXPORT showGraphicsLayerTree(const blink::GraphicsLayer*);
 #endif
 
 #endif // GraphicsLayer_h