--- a/widget/cocoa/nsPrintSettingsServiceX.h
+++ b/widget/cocoa/nsPrintSettingsServiceX.h
@@ -3,47 +3,52 @@
  * 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/. */
 
 #ifndef nsPrintSettingsServiceX_h_
 #define nsPrintSettingsServiceX_h_
 
 #include "nsPrintSettingsService.h"
 
-namespace mozilla
-{
-namespace embedding
-{
-  class PrintData;
+namespace mozilla {
+namespace embedding {
+class PrintData;
 } // namespace embedding
 } // namespace mozilla
 
 class nsPrintSettingsServiceX final : public nsPrintSettingsService
 {
 public:
   nsPrintSettingsServiceX() {}
   virtual ~nsPrintSettingsServiceX() {}
 
-  /*
+  /**
    * These serialize and deserialize methods are not symmetrical in that
    * printSettingsX != deserialize(serialize(printSettingsX)). This is because
    * the native print settings stored in the nsPrintSettingsX's NSPrintInfo
    * object are not fully serialized. Only the values needed for successful
    * printing are.
    */
   NS_IMETHODIMP SerializeToPrintData(nsIPrintSettings* aSettings,
                                      nsIWebBrowserPrint* aWBP,
-                                     mozilla::embedding::PrintData* data);
+                                     mozilla::embedding::PrintData* data) override;
+
   NS_IMETHODIMP DeserializeToPrintSettings(const mozilla::embedding::PrintData& data,
-                                           nsIPrintSettings* settings);
+                                           nsIPrintSettings* settings) override;
 
 protected:
-  nsresult   _CreatePrintSettings(nsIPrintSettings **_retval);
-  nsresult   ReadPrefs(nsIPrintSettings* aPS, const nsAString& aPrinterName, uint32_t aFlags);
-  nsresult   WritePrefs(nsIPrintSettings* aPS, const nsAString& aPrinterName, uint32_t aFlags);
+  nsresult ReadPrefs(nsIPrintSettings* aPS,
+                     const nsAString& aPrinterName,
+                     uint32_t aFlags) override;
+
+  nsresult WritePrefs(nsIPrintSettings* aPS,
+                      const nsAString& aPrinterName,
+                      uint32_t aFlags) override;
+
+  nsresult _CreatePrintSettings(nsIPrintSettings** _retval) override;
 
 private:
   /* Serialization done in child to be deserialized in the parent */
   nsresult SerializeToPrintDataChild(nsIPrintSettings* aSettings,
                                      nsIWebBrowserPrint* aWBP,
                                      mozilla::embedding::PrintData* data);
 
   /* Serialization done in parent to be deserialized in the child */

--- a/widget/gtk/nsPrintSettingsServiceGTK.h
+++ b/widget/gtk/nsPrintSettingsServiceGTK.h
@@ -4,34 +4,31 @@
  * 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/. */
 
 #ifndef nsPrintSettingsServiceGTK_h__
 #define nsPrintSettingsServiceGTK_h__
 
 #include "nsPrintSettingsService.h"
 
-namespace mozilla
-{
-namespace embedding
-{
-  class PrintData;
+namespace mozilla {
+namespace embedding {
+class PrintData;
 } // namespace embedding
 } // namespace mozilla
 
 class nsPrintSettingsServiceGTK final : public nsPrintSettingsService
 {
 public:
   nsPrintSettingsServiceGTK() {}
   virtual ~nsPrintSettingsServiceGTK() {}
 
   NS_IMETHODIMP SerializeToPrintData(nsIPrintSettings* aSettings,
                                      nsIWebBrowserPrint* aWBP,
-                                     mozilla::embedding::PrintData* data);
+                                     mozilla::embedding::PrintData* data) override;
+
   NS_IMETHODIMP DeserializeToPrintSettings(const mozilla::embedding::PrintData& data,
-                                           nsIPrintSettings* settings);
+                                           nsIPrintSettings* settings) override;
 
-  virtual nsresult _CreatePrintSettings(nsIPrintSettings **_retval);
+  nsresult _CreatePrintSettings(nsIPrintSettings** _retval) override;
 };
 
-
-
 #endif /* nsPrintSettingsServiceGTK_h__ */

--- a/widget/nsPrintSettingsService.h
+++ b/widget/nsPrintSettingsService.h
@@ -30,16 +30,21 @@ public:
   /**
    * method Init
    *  Initializes member variables. Every consumer that does manual
    *  creation (instead of do_CreateInstance) needs to call this method
    *  immediately after instantiation.
    */
   virtual nsresult Init();
 
+private:
+  // Copying is not supported.
+  nsPrintSettingsService(const nsPrintSettingsService& x) = delete;
+  nsPrintSettingsService& operator=(const nsPrintSettingsService& x) = delete;
+
 protected:
   virtual ~nsPrintSettingsService() {}
 
   void ReadBitFieldPref(const char * aPrefId, int32_t anOption);
   void WriteBitFieldPref(const char * aPrefId, int32_t anOption);
   void ReadJustification(const char * aPrefId, int16_t& aJust,
                          int16_t aInitValue);
   void WriteJustification(const char * aPrefId, int16_t aJust);
@@ -79,16 +84,11 @@ protected:
    * @return             printer settings instance
    */
   virtual nsresult _CreatePrintSettings(nsIPrintSettings **_retval);
 
   // Members
   nsCOMPtr<nsIPrintSettings> mGlobalPrintSettings;
 
   nsCString mPrefName;
-
-private:
-  // These are not supported and are not implemented!
-  nsPrintSettingsService(const nsPrintSettingsService& x) = delete;
-  nsPrintSettingsService& operator=(const nsPrintSettingsService& x) = delete;
 };
 
 #endif /* nsPrintSettingsService_h__ */

--- a/widget/windows/nsPrintSettingsServiceWin.h
+++ b/widget/windows/nsPrintSettingsServiceWin.h
@@ -16,18 +16,17 @@ class nsIWebBrowserPrint;
 class nsPrintSettingsServiceWin final : public nsPrintSettingsService
 {
 public:
   nsPrintSettingsServiceWin() {}
   virtual ~nsPrintSettingsServiceWin() {}
 
   NS_IMETHODIMP SerializeToPrintData(nsIPrintSettings* aSettings,
                                      nsIWebBrowserPrint* aWBP,
-                                     mozilla::embedding::PrintData* data);
+                                     mozilla::embedding::PrintData* data) override;
+
   NS_IMETHODIMP DeserializeToPrintSettings(const mozilla::embedding::PrintData& data,
-                                           nsIPrintSettings* settings);
+                                           nsIPrintSettings* settings) override;
 
-  virtual nsresult _CreatePrintSettings(nsIPrintSettings **_retval);
+  nsresult _CreatePrintSettings(nsIPrintSettings **_retval) override;
 };
 
-
-
 #endif /* nsPrintSettingsServiceWin_h__ */