Don't include headers from the layout API from other headers needlessly.

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

 // 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.
 
 #include "core/input/EventHandlingUtil.h"
 
 #include "core/frame/FrameView.h"
+#include "core/layout/api/LayoutViewItem.h"
 
 namespace blink {
 namespace EventHandlingUtil {
 
 HitTestResult hitTestResultInFrame(LocalFrame* frame, const LayoutPoint& point, HitTestRequest::HitTestRequestType hitType)
 {
     HitTestResult result(HitTestRequest(hitType), point);
 
     if (!frame || frame->contentLayoutItem().isNull())
         return result;
@@ skipping 35 matching lines @@
     case DispatchEventResult::CanceledBeforeDispatch:
         return WebInputEventResult::HandledSuppressed;
     default:
         NOTREACHED();
         return WebInputEventResult::HandledSystem;
     }
 }
 
 } // namespace EventHandlingUtil
 } // namespace blink