Merge two IsInDocument implementations.

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/layout/HitTestResult.h"
 #include "core/page/EventWithHitTestResults.h"
 #include "platform/geometry/LayoutPoint.h"
@@ skipping 13 matching lines @@
     HitTestRequest::HitTestRequestType hit_type = HitTestRequest::kReadOnly |
                                                   HitTestRequest::kActive);
 
 WebInputEventResult MergeEventResult(WebInputEventResult result_a,
                                      WebInputEventResult result_b);
 WebInputEventResult ToWebInputEventResult(DispatchEventResult);
 
 PaintLayer* LayerForNode(Node*);
 ScrollableArea* AssociatedScrollableArea(const PaintLayer*);
 
+bool IsInDocument(EventTarget*);
+
 ContainerNode* ParentForClickEvent(const Node&);
 
 LayoutPoint ContentPointFromRootFrame(LocalFrame*,
                                       const IntPoint& point_in_root_frame);
 
 MouseEventWithHitTestResults PerformMouseEventHitTest(LocalFrame*,
                                                       const HitTestRequest&,
                                                       const WebMouseEvent&);
 
 }  // namespace EventHandlingUtil
 
 }  // namespace blink
 
 #endif  // EventHandlingUtil_h