Implement elementsFromPoint

Source/core/layout/HitTestRequest.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
 */
 
 #ifndef HitTestRequest_h
 #define HitTestRequest_h
 
+#include "wtf/Assertions.h"
+
 namespace blink {
 
 class HitTestRequest {
 public:
     enum RequestType {
         ReadOnly = 1 << 1,
         Active = 1 << 2,
         Move = 1 << 3,
         Release = 1 << 4,
         IgnoreClipping = 1 << 5,
         SVGClipContent = 1 << 6,
         TouchEvent = 1 << 7,
         AllowChildFrameContent = 1 << 8,
         ChildFrameHitTest = 1 << 9,
         IgnorePointerEventsNone = 1 << 10,
+        // Collect a list of nodes instead of just one.
+        // (This is for elementsFromPoint and rect-based tests).
+        ListBased = 1 << 11,
+        // When using list-based testing, this flag causes us to continue hit
+        // testing after a hit has been found.
+        PenetratingList = 1 << 12,
     };
 
     typedef unsigned HitTestRequestType;
 
     HitTestRequest(HitTestRequestType requestType)
         : m_requestType(requestType)
     {
+        // Penetrating lists should also be list-based.
+        ASSERT(!(requestType & PenetratingList) || (requestType & ListBased));
     }
 
     bool readOnly() const { return m_requestType & ReadOnly; }
     bool active() const { return m_requestType & Active; }
     bool move() const { return m_requestType & Move; }
     bool release() const { return m_requestType & Release; }
     bool ignoreClipping() const { return m_requestType & IgnoreClipping; }
     bool svgClipContent() const { return m_requestType & SVGClipContent; }
     bool touchEvent() const { return m_requestType & TouchEvent; }
     bool allowsChildFrameContent() const { return m_requestType & AllowChildFrameContent; }
     bool isChildFrameHitTest() const { return m_requestType & ChildFrameHitTest; }
     bool ignorePointerEventsNone() const { return m_requestType & IgnorePointerEventsNone; }
+    bool listBased() const { return m_requestType & ListBased; }
+    bool penetratingList() const { return m_requestType & PenetratingList; }
 
     // Convenience functions
     bool touchMove() const { return move() && touchEvent(); }
 
     HitTestRequestType type() const { return m_requestType; }
 
 private:
     HitTestRequestType m_requestType;
 };
 
 } // namespace blink
 
 #endif // HitTestRequest_h