--- a/widget/MiscEvents.h
+++ b/widget/MiscEvents.h
@@ -151,17 +151,17 @@ private:
   friend class dom::PBrowserParent;
   friend class dom::PBrowserChild;
 
 public:
   virtual WidgetPluginEvent* AsPluginEvent() override { return this; }
 
   WidgetPluginEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget)
     : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, ePluginEventClass)
-    , retargetToFocusedDocument(false)
+    , mRetargetToFocusedDocument(false)
   {
   }
 
   virtual WidgetEvent* Duplicate() const override
   {
     // NOTE: PluginEvent has to be dispatched to nsIFrame::HandleEvent().
     //       So, this event needs to support Duplicate().
     MOZ_ASSERT(mClass == ePluginEventClass,
@@ -170,24 +170,24 @@ public:
     WidgetPluginEvent* result = new WidgetPluginEvent(false, mMessage, nullptr);
     result->AssignPluginEventData(*this, true);
     result->mFlags = mFlags;
     return result;
   }
 
   // If true, this event needs to be retargeted to focused document.
   // Otherwise, never retargeted. Defaults to false.
-  bool retargetToFocusedDocument;
+  bool mRetargetToFocusedDocument;
 
   void AssignPluginEventData(const WidgetPluginEvent& aEvent,
                              bool aCopyTargets)
   {
     AssignGUIEventData(aEvent, aCopyTargets);
 
-    retargetToFocusedDocument = aEvent.retargetToFocusedDocument;
+    mRetargetToFocusedDocument = aEvent.mRetargetToFocusedDocument;
   }
 
 protected:
   WidgetPluginEvent()
   {
   }
 };
 

--- a/widget/WidgetEventImpl.cpp
+++ b/widget/WidgetEventImpl.cpp
@@ -203,24 +203,24 @@ WidgetEvent::HasPluginActivationEventMes
  *
  * Specific event checking methods.
  ******************************************************************************/
 
 bool
 WidgetEvent::IsRetargetedNativeEventDelivererForPlugin() const
 {
   const WidgetPluginEvent* pluginEvent = AsPluginEvent();
-  return pluginEvent && pluginEvent->retargetToFocusedDocument;
+  return pluginEvent && pluginEvent->mRetargetToFocusedDocument;
 }
 
 bool
 WidgetEvent::IsNonRetargetedNativeEventDelivererForPlugin() const
 {
   const WidgetPluginEvent* pluginEvent = AsPluginEvent();
-  return pluginEvent && !pluginEvent->retargetToFocusedDocument;
+  return pluginEvent && !pluginEvent->mRetargetToFocusedDocument;
 }
 
 bool
 WidgetEvent::IsIMERelatedEvent() const
 {
   return HasIMEEventMessage() || IsQueryContentEvent() || IsSelectionEvent();
 }
 

--- a/widget/nsGUIEventIPC.h
+++ b/widget/nsGUIEventIPC.h
@@ -880,24 +880,24 @@ struct ParamTraits<mozilla::widget::IMEN
 template<>
 struct ParamTraits<mozilla::WidgetPluginEvent>
 {
   typedef mozilla::WidgetPluginEvent paramType;
 
   static void Write(Message* aMsg, const paramType& aParam)
   {
     WriteParam(aMsg, static_cast<mozilla::WidgetGUIEvent>(aParam));
-    WriteParam(aMsg, aParam.retargetToFocusedDocument);
+    WriteParam(aMsg, aParam.mRetargetToFocusedDocument);
   }
 
   static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
   {
     return ReadParam(aMsg, aIter,
                      static_cast<mozilla::WidgetGUIEvent*>(aResult)) &&
-           ReadParam(aMsg, aIter, &aResult->retargetToFocusedDocument);
+           ReadParam(aMsg, aIter, &aResult->mRetargetToFocusedDocument);
   }
 };
 
 template<>
 struct ParamTraits<mozilla::WritingMode>
 {
   typedef mozilla::WritingMode paramType;
 

--- a/widget/windows/nsWindowBase.cpp
+++ b/widget/windows/nsWindowBase.cpp
@@ -26,17 +26,17 @@ nsWindowBase::DispatchPluginEvent(const 
   WidgetPluginEvent pluginEvent(true, ePluginInputEvent, this);
   LayoutDeviceIntPoint point(0, 0);
   InitEvent(pluginEvent, &point);
   NPEvent npEvent;
   npEvent.event = aMsg.message;
   npEvent.wParam = aMsg.wParam;
   npEvent.lParam = aMsg.lParam;
   pluginEvent.mPluginEvent.Copy(npEvent);
-  pluginEvent.retargetToFocusedDocument = true;
+  pluginEvent.mRetargetToFocusedDocument = true;
   return DispatchWindowEvent(&pluginEvent);
 }
 
 // static
 bool
 nsWindowBase::InitTouchInjection()
 {
   if (!sTouchInjectInitialized) {