Revert of Revert of Revert of Initial draft - modify ViewportAnchor to know about both inner and outer viewports.

Source/web/ViewportAnchor.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include "platform/geometry/IntRect.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/heap/Handle.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
 
 class EventHandler;
 class IntSize;
 class Node;
-class ScrollView;
 
 // ViewportAnchor provides a way to anchor a viewport origin to a DOM node.
 // In particular, the user supplies the current viewport (in CSS coordinates)
 // and an anchor point (in view coordinates, e.g., (0, 0) == viewport origin,
 // (0.5, 0) == viewport top center). The anchor point tracks the underlying DOM
 // node; as the node moves or the view is resized, the viewport anchor maintains
 // its orientation relative to the node, and the viewport origin maintains its
 // orientation relative to the anchor.
 class ViewportAnchor {
     STACK_ALLOCATED();
 public:
     explicit ViewportAnchor(EventHandler*);
 
-    void setAnchor(const IntRect& outerViewRect, const IntRect& innerViewRect, const FloatSize& anchorInViewCoords);
+    void setAnchor(const IntRect& viewRect, const FloatSize& anchorInViewCoords);
 
-    void computeOrigins(const ScrollView&, const FloatSize& innerSize,
-        IntPoint& mainFrameOffset, FloatPoint& pinchViewportOffset) const;
-
-private:
-    FloatPoint getInnerOrigin(const FloatSize& innerSize) const;
+    IntPoint computeOrigin(const IntSize& currentViewSize) const;
 
 private:
     RawPtrWillBeMember<EventHandler> m_eventHandler;
 
-    // Inner viewport origin in the reference frame of the document in CSS pixels
-    FloatPoint m_pinchViewportInDocument;
-
-    // Inner viewport origin in the reference frame of the outer viewport
-    // normalized to the outer viewport size.
-    FloatSize m_normalizedPinchViewportOffset;
+    IntRect m_viewRect;
 
     RefPtrWillBeMember<Node> m_anchorNode;
     LayoutRect m_anchorNodeBounds;
 
-    FloatSize m_anchorInInnerViewCoords;
+    FloatSize m_anchorInViewCoords;
     FloatSize m_anchorInNodeCoords;
 };
 
 } // namespace blink
 
-#endif
+ #endif