Implement position: sticky updates on compositor

third_party/WebKit/public/platform/WebLayer.h

 /*
  * Copyright (C) 2011 Google Inc. 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 35 matching lines @@
 class LayerClient;
 class FilterOperations;
 struct ElementId;
 }
 
 namespace blink {
 
 class WebLayerScrollClient;
 struct WebFloatPoint;
 struct WebLayerPositionConstraint;
+struct WebLayerStickyPositionConstraint;
 
 class WebLayer {
 public:
     virtual ~WebLayer() { }
 
     // Returns a positive ID that will be unique across all WebLayers allocated in this process.
     virtual int id() const = 0;
 
     // Sets a region of the layer as invalid, i.e. needs to update its content.
     virtual void invalidateRect(const WebRect&) = 0;
@@ skipping 115 matching lines @@
     virtual WebVector<WebRect> touchEventHandlerRegion() const = 0;
 
     virtual void setIsContainerForFixedPositionLayers(bool) = 0;
     virtual bool isContainerForFixedPositionLayers() const = 0;
 
     // This function sets layer position constraint. The constraint will be used
     // to adjust layer position during threaded scrolling.
     virtual void setPositionConstraint(const WebLayerPositionConstraint&) = 0;
     virtual WebLayerPositionConstraint positionConstraint() const = 0;
 
+    // Sets the sticky position constraint. This will be used to adjust sticky
+    // position objects during threaded scrolling.
+    virtual void setStickyPositionConstraint(const WebLayerStickyPositionConstraint&) = 0;
+    virtual WebLayerStickyPositionConstraint stickyPositionConstraint() const = 0;
+
     // The scroll client is notified when the scroll position of the WebLayer
     // changes. Only a single scroll client can be set for a WebLayer at a time.
     // The WebLayer does not take ownership of the scroll client, and it is the
     // responsibility of the client to reset the layer's scroll client before
     // deleting the scroll client.
     virtual void setScrollClient(WebLayerScrollClient*) = 0;
 
     // Sets the cc-side layer client.
     virtual void setLayerClient(cc::LayerClient*) = 0;
 
     // Gets the underlying cc layer.
     virtual const cc::Layer* ccLayer() const = 0;
     virtual cc::Layer* ccLayer() = 0;
 
     virtual void setElementId(const cc::ElementId&) = 0;
     virtual cc::ElementId elementId() const = 0;
 
     virtual void setCompositorMutableProperties(uint32_t) = 0;
     virtual uint32_t compositorMutableProperties() const = 0;
 
     virtual void setHasWillChangeTransformHint(bool) = 0;
 };
 
 } // namespace blink
 
 #endif // WebLayer_h