Intersection Observer support for OOPIF

third_party/WebKit/public/web/WebFrameWidget.h

 /*
  * Copyright (C) 2014 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 94 matching lines @@
   virtual void dragTargetDrop(const WebDragData&,
                               const WebPoint& pointInViewport,
                               const WebPoint& screenPoint,
                               int modifiers) = 0;
 
   // Notifies the WebFrameWidget that a drag has terminated.
   virtual void dragSourceEndedAt(const WebPoint& pointInViewport,
                                  const WebPoint& screenPoint,
                                  WebDragOperation) = 0;
 
-  // Notfies the WebFrameWidget that the system drag and drop operation has
+  // Notifies the WebFrameWidget that the system drag and drop operation has
   // ended.
   virtual void dragSourceSystemDragEnded() = 0;
+
+  // Constrains the viewport intersection for use by IntersectionObserver.
+  // This is needed for out-of-process iframes to know if they are clipped
+  // by ancestor frames in another process.
+  virtual void setRemoteViewportIntersection(const WebRect&) {}
 };
 
 }  // namespace blink
 
 #endif