4 files changed, 7 insertions, 31 deletions
diff --git a/dom/base/FragmentOrElement.cpp b/dom/base/FragmentOrElement.cpp
index 5b2fabd8d..676665c09 100644
--- a/dom/base/FragmentOrElement.cpp
+++ b/dom/base/FragmentOrElement.cpp
@@ -825,7 +825,7 @@ nsIContent::GetEventTargetParent(EventChainPreVisitor& aVisitor)
       ((this == aVisitor.mEvent->mOriginalTarget &&
         !ChromeOnlyAccess()) || isAnonForEvents || GetShadowRoot())) {
      nsCOMPtr<nsIContent> relatedTarget =
-       do_QueryInterface(aVisitor.mEvent->AsMouseEvent()->relatedTarget);
+       do_QueryInterface(aVisitor.mEvent->AsMouseEvent()->mRelatedTarget);
     if (relatedTarget &&
         relatedTarget->OwnerDoc() == OwnerDoc()) {
 
diff --git a/dom/events/Event.cpp b/dom/events/Event.cpp
index def298228..aff65b40f 100755
--- a/dom/events/Event.cpp
+++ b/dom/events/Event.cpp
@@ -158,18 +158,11 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Event)
     tmp->mEvent->mTarget = nullptr;
     tmp->mEvent->mCurrentTarget = nullptr;
     tmp->mEvent->mOriginalTarget = nullptr;
+    tmp->mEvent->mRelatedTarget = nullptr;
     switch (tmp->mEvent->mClass) {
-      case eMouseEventClass:
-      case eMouseScrollEventClass:
-      case eWheelEventClass:
-      case eSimpleGestureEventClass:
-      case ePointerEventClass:
-        tmp->mEvent->AsMouseEventBase()->relatedTarget = nullptr;
-        break;
       case eDragEventClass: {
         WidgetDragEvent* dragEvent = tmp->mEvent->AsDragEvent();
         dragEvent->mDataTransfer = nullptr;
-        dragEvent->relatedTarget = nullptr;
         break;
       }
       case eClipboardEventClass:
@@ -178,9 +171,6 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Event)
       case eMutationEventClass:
         tmp->mEvent->AsMutationEvent()->mRelatedNode = nullptr;
         break;
-      case eFocusEventClass:
-        tmp->mEvent->AsFocusEvent()->mRelatedTarget = nullptr;
-        break;
       default:
         break;
     }
@@ -196,21 +186,12 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(Event)
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mTarget)
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mCurrentTarget)
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mOriginalTarget)
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mRelatedTarget)
     switch (tmp->mEvent->mClass) {
-      case eMouseEventClass:
-      case eMouseScrollEventClass:
-      case eWheelEventClass:
-      case eSimpleGestureEventClass:
-      case ePointerEventClass:
-        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->relatedTarget");
-        cb.NoteXPCOMChild(tmp->mEvent->AsMouseEventBase()->relatedTarget);
-        break;
       case eDragEventClass: {
         WidgetDragEvent* dragEvent = tmp->mEvent->AsDragEvent();
         NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mDataTransfer");
         cb.NoteXPCOMChild(dragEvent->mDataTransfer);
-        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->relatedTarget");
-        cb.NoteXPCOMChild(dragEvent->relatedTarget);
         break;
       }
       case eClipboardEventClass:
@@ -221,10 +202,6 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(Event)
         NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mRelatedNode");
         cb.NoteXPCOMChild(tmp->mEvent->AsMutationEvent()->mRelatedNode);
         break;
-      case eFocusEventClass:
-        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mRelatedTarget");
-        cb.NoteXPCOMChild(tmp->mEvent->AsFocusEvent()->mRelatedTarget);
-        break;
       default:
         break;
     }
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 459521b83..cc3bd3f5a 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -3906,13 +3906,13 @@ CreateMouseOrPointerWidgetEvent(WidgetMouseEvent* aMouseEvent,
     newPointerEvent->mWidth = sourcePointer->mWidth;
     newPointerEvent->mHeight = sourcePointer->mHeight;
     newPointerEvent->inputSource = sourcePointer->inputSource;
-    newPointerEvent->relatedTarget = aRelatedContent;
+    newPointerEvent->mRelatedTarget = aRelatedContent;
     aNewEvent = newPointerEvent.forget();
   } else {
     aNewEvent =
       new WidgetMouseEvent(aMouseEvent->IsTrusted(), aMessage,
                            aMouseEvent->mWidget, WidgetMouseEvent::eReal);
-    aNewEvent->relatedTarget = aRelatedContent;
+    aNewEvent->mRelatedTarget = aRelatedContent;
   }
   aNewEvent->mRefPoint = aMouseEvent->mRefPoint;
   aNewEvent->mModifiers = aMouseEvent->mModifiers;
diff --git a/dom/events/MouseEvent.cpp b/dom/events/MouseEvent.cpp
index 5e540ac5b..415e626c5 100644
--- a/dom/events/MouseEvent.cpp
+++ b/dom/events/MouseEvent.cpp
@@ -79,7 +79,7 @@ MouseEvent::InitMouseEvent(const nsAString& aType,
     case ePointerEventClass:
     case eSimpleGestureEventClass: {
       WidgetMouseEventBase* mouseEventBase = mEvent->AsMouseEventBase();
-      mouseEventBase->relatedTarget = aRelatedTarget;
+      mouseEventBase->mRelatedTarget = aRelatedTarget;
       mouseEventBase->button = aButton;
       mouseEventBase->InitBasicModifiers(aCtrlKey, aAltKey, aShiftKey, aMetaKey);
       mClientPoint.x = aClientX;
@@ -295,8 +295,7 @@ MouseEvent::GetRelatedTarget()
     case eDragEventClass:
     case ePointerEventClass:
     case eSimpleGestureEventClass:
-      relatedTarget =
-        do_QueryInterface(mEvent->AsMouseEventBase()->relatedTarget);
+      relatedTarget = mEvent->AsMouseEventBase()->mRelatedTarget;
       break;
     default:
       break;