Expose scroll customization for touch to JS (behind REF).

Source/core/page/scrolling/ScrollState.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ScrollState_h
 #define ScrollState_h
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/CoreExport.h"
@@ skipping 37 matching lines @@
     // True if this is the last event for this scroll.
     bool isEnding() const { return m_isEnding; }
     // True if this scroll is the direct result of user input.
     bool fromUserInput() const { return m_fromUserInput; }
     // True if this scroll is allowed to bubble upwards.
     bool shouldPropagate() const { return m_shouldPropagate; }
 
     // Non web exposed methods.
     void consumeDeltaNative(double x, double y);
 
+    // TODO(tdresser): this needs to be web exposed. See crbug.com/483091.
     void setScrollChain(WillBeHeapDeque<RefPtrWillBeMember<Element>> scrollChain)
     {
         m_scrollChain = scrollChain;
     }
 
     void setCurrentNativeScrollingElement(Element* element)
     {
         m_currentNativeScrollingElement = element;
     }
 
@@ skipping 43 matching lines @@
     // Whether the scroll sequence has had any delta consumed, in the
     // current frame, or any child frames.
     bool m_deltaConsumedForScrollSequence;
 
     WillBeHeapDeque<RefPtrWillBeMember<Element>> m_scrollChain;
 };
 
 } // namespace blink
 
 #endif // ScrollState_h