--- a/dom/base/nsQueryContentEventResult.cpp
+++ b/dom/base/nsQueryContentEventResult.cpp
@@ -1,17 +1,18 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "nsQueryContentEventResult.h"
 #include "nsIWidget.h"
 #include "nsPoint.h"
+#include "nsQueryContentEventResult.h"
+#include "mozilla/Move.h"
 #include "mozilla/TextEvents.h"
 
 using namespace mozilla;
 
 /******************************************************************************
  * Is*PropertyAvailable() methods which check if the property is available
  * (valid) with the event message.
  ******************************************************************************/
@@ -217,26 +218,28 @@ nsQueryContentEventResult::GetCharacterR
   *aWidth = mRectArray[aOffset].width;
   *aHeight = mRectArray[aOffset].height;
 
   return NS_OK;
 }
 
 void
 nsQueryContentEventResult::SetEventResult(nsIWidget* aWidget,
-                                          const WidgetQueryContentEvent &aEvent)
+                                          WidgetQueryContentEvent &aEvent)
 {
   mEventMessage = aEvent.mMessage;
   mSucceeded = aEvent.mSucceeded;
   mReversed = aEvent.mReply.mReversed;
   mRect = aEvent.mReply.mRect;
   mOffset = aEvent.mReply.mOffset;
   mTentativeCaretOffset = aEvent.mReply.mTentativeCaretOffset;
   mString = aEvent.mReply.mString;
-  mRectArray = aEvent.mReply.mRectArray;
+  mRectArray = mozilla::Move(aEvent.mReply.mRectArray);
+  // Mark as result that is longer used.
+  aEvent.mSucceeded = false;
 
   if (!IsRectRelatedPropertyAvailable(mEventMessage) ||
       !aWidget || !mSucceeded) {
     return;
   }
 
   nsIWidget* topWidget = aWidget->GetTopLevelWidget();
   if (!topWidget || topWidget == aWidget) {

--- a/dom/base/nsQueryContentEventResult.h
+++ b/dom/base/nsQueryContentEventResult.h
@@ -19,17 +19,17 @@ class nsIWidget;
 class nsQueryContentEventResult final : public nsIQueryContentEventResult
 {
 public:
   nsQueryContentEventResult();
   NS_DECL_ISUPPORTS
   NS_DECL_NSIQUERYCONTENTEVENTRESULT
 
   void SetEventResult(nsIWidget* aWidget,
-                      const mozilla::WidgetQueryContentEvent &aEvent);
+                      mozilla::WidgetQueryContentEvent& aEvent);
 
 protected:
   ~nsQueryContentEventResult();
 
   mozilla::EventMessage mEventMessage;
 
   uint32_t mOffset;
   uint32_t mTentativeCaretOffset;

--- a/widget/ContentCache.cpp
+++ b/widget/ContentCache.cpp
@@ -7,16 +7,17 @@
 
 #include "mozilla/ContentCache.h"
 #include "mozilla/IMEStateManager.h"
 #include "mozilla/Logging.h"
 #include "mozilla/TextComposition.h"
 #include "mozilla/TextEvents.h"
 #include "nsIWidget.h"
 #include "mozilla/RefPtr.h"
+#include "mozilla/Move.h"
 
 namespace mozilla {
 
 using namespace widget;
 
 static const char*
 GetBoolName(bool aBool)
 {
@@ -309,17 +310,17 @@ ContentCacheInChild::CacheTextRects(nsIW
     uint32_t length = textComposition->LastData().Length();
     mTextRectArray.mStart = mCompositionStart;
 
     nsEventStatus status = nsEventStatus_eIgnore;
     WidgetQueryContentEvent textRects(true, eQueryTextRectArray, aWidget);
     textRects.InitForQueryTextRectArray(mTextRectArray.mStart, length);
     aWidget->DispatchEvent(&textRects, status);
 
-    mTextRectArray.mRects = textRects.mReply.mRectArray;
+    mTextRectArray.mRects = Move(textRects.mReply.mRectArray);
   }
 
   if (mTextRectArray.InRange(mSelection.mAnchor)) {
     mSelection.mAnchorCharRect = mTextRectArray.GetRect(mSelection.mAnchor);
   } else {
     LayoutDeviceIntRect charRect;
     if (NS_WARN_IF(!QueryCharRect(aWidget, mSelection.mAnchor, charRect))) {
       MOZ_LOG(sContentCacheLog, LogLevel::Error,