MouseWheelEventManager is added to handle wheel events.

third_party/WebKit/Source/core/input/EventHandlingUtil.h

 // Copyright 2016 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 EventHandlingUtil_h
 #define EventHandlingUtil_h
 
 #include "core/frame/LocalFrame.h"
 #include "core/layout/HitTestResult.h"
 #include "core/page/EventWithHitTestResults.h"
@@ skipping 25 matching lines @@
 
 ContainerNode* ParentForClickEvent(const Node&);
 
 LayoutPoint ContentPointFromRootFrame(LocalFrame*,
                                       const IntPoint& point_in_root_frame);
 
 MouseEventWithHitTestResults PerformMouseEventHitTest(LocalFrame*,
                                                       const HitTestRequest&,
                                                       const WebMouseEvent&);
 
+LocalFrame* SubframeForHitTestResult(const MouseEventWithHitTestResults&);
+
+LocalFrame* SubframeForTargetNode(Node*);
+
 class PointerEventTarget {
   DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
 
  public:
   DEFINE_INLINE_TRACE() {
     visitor->Trace(target_node);
     visitor->Trace(target_frame);
   }
 
   Member<Node> target_node;
   Member<LocalFrame> target_frame;
   String region;
 };
 
 }  // namespace EventHandlingUtil
 
 }  // namespace blink
 
 WTF_ALLOW_INIT_WITH_MEM_FUNCTIONS(blink::EventHandlingUtil::PointerEventTarget);
 
 #endif  // EventHandlingUtil_h