MouseWheelEventManager is added to handle wheel events.

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/LocalFrame.h"
 #include "core/frame/LocalFrameView.h"
+#include "core/layout/LayoutEmbeddedContent.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "public/platform/WebMouseEvent.h"
 
 namespace blink {
 namespace EventHandlingUtil {
 
 HitTestResult HitTestResultInFrame(
     LocalFrame* frame,
@@ skipping 102 matching lines @@
   DCHECK(frame);
   DCHECK(frame->GetDocument());
 
   return frame->GetDocument()->PerformMouseEventHitTest(
       request,
       ContentPointFromRootFrame(frame,
                                 FlooredIntPoint(mev.PositionInRootFrame())),
       mev);
 }
 
+LocalFrame* SubframeForTargetNode(Node* node) {
+  if (!node)
+    return nullptr;
+
+  LayoutObject* layout_object = node->GetLayoutObject();
+  if (!layout_object || !layout_object->IsLayoutEmbeddedContent())
+    return nullptr;
+
+  LocalFrameView* frame_view =
+      ToLayoutEmbeddedContent(layout_object)->ChildFrameView();
+  if (!frame_view)
+    return nullptr;
+
+  return &frame_view->GetFrame();
+}
+
+LocalFrame* SubframeForHitTestResult(
+    const MouseEventWithHitTestResults& hit_test_result) {
+  if (!hit_test_result.IsOverEmbeddedContentView())
+    return nullptr;
+  return SubframeForTargetNode(hit_test_result.InnerNode());
+}
+
 }  // namespace EventHandlingUtil
 }  // namespace blink