--- a/dom/events/UIEvent.cpp
+++ b/dom/events/UIEvent.cpp
@@ -128,17 +128,17 @@ void UIEvent::InitUIEvent(const nsAStrin
 
   Event::InitEvent(typeArg, canBubbleArg, cancelableArg);
 
   mDetail = detailArg;
   mView = viewArg ? viewArg->GetOuterWindow() : nullptr;
 }
 
 already_AddRefed<nsIContent> UIEvent::GetRangeParentContentAndOffset(
-    int32_t* aOffset) {
+    int32_t* aOffset) const {
   if (NS_WARN_IF(!mPresContext)) {
     return nullptr;
   }
   RefPtr<PresShell> presShell = mPresContext->GetPresShell();
   if (NS_WARN_IF(!presShell)) {
     return nullptr;
   }
   nsCOMPtr<nsIContent> container;

--- a/dom/events/UIEvent.h
+++ b/dom/events/UIEvent.h
@@ -80,17 +80,17 @@ class UIEvent : public Event {
   MOZ_CAN_RUN_SCRIPT already_AddRefed<nsIContent> GetRangeParentContent() {
     return GetRangeParentContentAndOffset(nullptr);
   }
   /**
    * aOffset is optional (i.e., can be nullptr), but when you call this with
    * nullptr, you should use GetRangeParentContent() instead.
    */
   MOZ_CAN_RUN_SCRIPT already_AddRefed<nsIContent>
-  GetRangeParentContentAndOffset(int32_t* aOffset);
+  GetRangeParentContentAndOffset(int32_t* aOffset) const;
 
   /**
    * If you also need to compute range parent in C++ code, you should use
    * GetRangeParentContentAndOffset() instead.
    */
   MOZ_CAN_RUN_SCRIPT int32_t RangeOffset() const;
 
  protected:

--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -4687,17 +4687,17 @@ bool EditorBase::IsActiveInDOMWindow() c
   }
   nsPIDOMWindowOuter* ourWindow = document->GetWindow();
   nsCOMPtr<nsPIDOMWindowOuter> win;
   nsIContent* content = nsFocusManager::GetFocusedDescendant(
       ourWindow, nsFocusManager::eOnlyCurrentWindow, getter_AddRefs(win));
   return SameCOMIdentity(content, piTarget);
 }
 
-bool EditorBase::IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) {
+bool EditorBase::IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) const {
   // If the event is trusted, the event should always cause input.
   if (NS_WARN_IF(!aGUIEvent)) {
     return false;
   }
 
   // If this is dispatched by using cordinates but this editor doesn't have
   // focus, we shouldn't handle it.
   if (aGUIEvent->IsUsingCoordinates()) {

--- a/editor/libeditor/EditorBase.h
+++ b/editor/libeditor/EditorBase.h
@@ -560,17 +560,17 @@ class EditorBase : public nsIEditor,
   virtual nsIContent* GetFocusedContentForIME() const;
 
   /**
    * Whether the aGUIEvent should be handled by this editor or not.  When this
    * returns false, The aGUIEvent shouldn't be handled on this editor,
    * i.e., The aGUIEvent should be handled by another inner editor or ancestor
    * elements.
    */
-  virtual bool IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent);
+  virtual bool IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) const;
 
   /**
    * FindSelectionRoot() returns a selection root of this editor when aNode
    * gets focus.  aNode must be a content node or a document node.  When the
    * target isn't a part of this editor, returns nullptr.  If this is for
    * designMode, you should set the document node to aNode except that an
    * element in the document has focus.
    */

--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@@ -6127,17 +6127,17 @@ bool HTMLEditor::OurWindowHasFocus() con
   Document* document = GetDocument();
   if (NS_WARN_IF(!document)) {
     return false;
   }
   nsPIDOMWindowOuter* ourWindow = document->GetWindow();
   return ourWindow == focusedWindow;
 }
 
-bool HTMLEditor::IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) {
+bool HTMLEditor::IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) const {
   if (!EditorBase::IsAcceptableInputEvent(aGUIEvent)) {
     return false;
   }
 
   // While there is composition, all composition events in its top level
   // window are always fired on the composing editor.  Therefore, if this
   // editor has composition, the composition events should be handled in this
   // editor.

--- a/editor/libeditor/HTMLEditor.h
+++ b/editor/libeditor/HTMLEditor.h
@@ -166,17 +166,17 @@ class HTMLEditor final : public TextEdit
 
   MOZ_CAN_RUN_SCRIPT virtual nsresult HandleKeyPressEvent(
       WidgetKeyboardEvent* aKeyboardEvent) override;
   virtual nsIContent* GetFocusedContent() const override;
   virtual nsIContent* GetFocusedContentForIME() const override;
   virtual bool IsActiveInDOMWindow() const override;
   virtual dom::EventTarget* GetDOMEventTarget() const override;
   virtual Element* FindSelectionRoot(nsINode* aNode) const override;
-  virtual bool IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) override;
+  virtual bool IsAcceptableInputEvent(WidgetGUIEvent* aGUIEvent) const override;
   virtual nsresult GetPreferredIMEState(widget::IMEState* aState) override;
 
   /**
    * GetBackgroundColorState() returns what the background color of the
    * selection.
    *
    * @param aMixed      true if there is more than one font color
    * @param aOutColor   Color string. "" is returned for none.