Convert drag event position to root frame.

third_party/WebKit/public/web/WebView.h

 /*
  * Copyright (C) 2009, 2010, 2011, 2012 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 352 matching lines @@
 
   // Do a hit test at given point and return the HitTestResult.
   virtual WebHitTestResult hitTestResultAt(const WebPoint&) = 0;
 
   // Do a hit test equivalent to what would be done for a GestureTap event
   // that has width/height corresponding to the supplied |tapArea|.
   virtual WebHitTestResult hitTestResultForTap(const WebPoint& tapPoint,
                                                const WebSize& tapArea) = 0;
 
   // Notifies the WebView that a drag has terminated.
-  virtual void dragSourceEndedAt(const WebPoint& clientPoint,
+  virtual void dragSourceEndedAt(const WebPoint& pointInViewport,
                                  const WebPoint& screenPoint,
                                  WebDragOperation operation) = 0;
 
   // Notfies the WebView that the system drag and drop operation has ended.
   virtual void dragSourceSystemDragEnded() = 0;
 
   // Callback methods when a drag-and-drop operation is trying to drop
   // something on the WebView.
   virtual WebDragOperation dragTargetDragEnter(
       const WebDragData&,
-      const WebPoint& clientPoint,
+      const WebPoint& pointInViewport,
       const WebPoint& screenPoint,
       WebDragOperationsMask operationsAllowed,
       int modifiers) = 0;
   virtual WebDragOperation dragTargetDragOver(
-      const WebPoint& clientPoint,
+      const WebPoint& pointInViewport,
       const WebPoint& screenPoint,
       WebDragOperationsMask operationsAllowed,
       int modifiers) = 0;
   virtual void dragTargetDragLeave() = 0;
   virtual void dragTargetDrop(const WebDragData&,
-                              const WebPoint& clientPoint,
+                              const WebPoint& pointInViewport,
                               const WebPoint& screenPoint,
                               int modifiers) = 0;
 
   // Retrieves a list of spelling markers.
   virtual void spellingMarkers(WebVector<uint32_t>* markers) = 0;
   virtual void removeSpellingMarkersUnderWords(
       const WebVector<WebString>& words) = 0;
 
   // Support for resource loading initiated by plugins -------------------
 
@@ skipping 125 matching lines @@
   // completed.
   WebWidget* widget() { return this; }
 
  protected:
   ~WebView() {}
 };
 
 }  // namespace blink
 
 #endif