diff --git a/gfx/thebes/gfxDWriteFonts.cpp b/gfx/thebes/gfxDWriteFonts.cpp
index 249e846f79ce..43fc3325d738 100644
--- a/gfx/thebes/gfxDWriteFonts.cpp
+++ b/gfx/thebes/gfxDWriteFonts.cpp
@@ -126,11 +126,11 @@ gfxDWriteFont::UpdateClearTypeUsage()
   mUseClearType = UsingClearType();
 }
 
-gfxFont*
+UniquePtr<gfxFont>
 gfxDWriteFont::CopyWithAntialiasOption(AntialiasOption anAAOption)
 {
-    return new gfxDWriteFont(static_cast<gfxDWriteFontEntry*>(mFontEntry.get()),
-                             &mStyle, mNeedsBold, anAAOption);
+    auto entry = static_cast<gfxDWriteFontEntry*>(mFontEntry.get());
+    return MakeUnique<gfxDWriteFont>(entry, &mStyle, mNeedsBold, anAAOption);
 }
 
 const gfxFont::Metrics&
diff --git a/gfx/thebes/gfxDWriteFonts.h b/gfx/thebes/gfxDWriteFonts.h
index e8d4e4e1eb30..cc39f6c20d96 100644
--- a/gfx/thebes/gfxDWriteFonts.h
+++ b/gfx/thebes/gfxDWriteFonts.h
@@ -31,7 +31,7 @@ public:
 
     static void UpdateClearTypeUsage();
 
-    virtual gfxFont*
+    mozilla::UniquePtr<gfxFont>
     CopyWithAntialiasOption(AntialiasOption anAAOption) override;
 
     virtual uint32_t GetSpaceGlyph() override;
diff --git a/gfx/thebes/gfxFont.cpp b/gfx/thebes/gfxFont.cpp
index 21c1d9f4b060..59965bbcb3bb 100644
--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@@ -2305,7 +2305,7 @@ gfxFont::Measure(const gfxTextRun *aTextRun,
     if (aBoundingBoxType == TIGHT_HINTED_OUTLINE_EXTENTS &&
         mAntialiasOption != kAntialiasNone) {
         if (!mNonAAFont) {
-            mNonAAFont.reset(CopyWithAntialiasOption(kAntialiasNone));
+            mNonAAFont = Move(CopyWithAntialiasOption(kAntialiasNone));
         }
         // if font subclass doesn't implement CopyWithAntialiasOption(),
         // it will return null and we'll proceed to use the existing font
diff --git a/gfx/thebes/gfxFont.h b/gfx/thebes/gfxFont.h
index e58b21ad1e02..c9ec10e5eded 100644
--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@@ -1430,7 +1430,8 @@ public:
 
     virtual cairo_scaled_font_t* GetCairoScaledFont() { return mScaledFont; }
 
-    virtual gfxFont* CopyWithAntialiasOption(AntialiasOption anAAOption) {
+    virtual mozilla::UniquePtr<gfxFont>
+    CopyWithAntialiasOption(AntialiasOption anAAOption) {
         // platforms where this actually matters should override
         return nullptr;
     }
diff --git a/gfx/thebes/gfxGDIFont.cpp b/gfx/thebes/gfxGDIFont.cpp
index e6ceeaf6d8b4..0db13f422a61 100644
--- a/gfx/thebes/gfxGDIFont.cpp
+++ b/gfx/thebes/gfxGDIFont.cpp
@@ -72,11 +72,11 @@ gfxGDIFont::~gfxGDIFont()
     delete mMetrics;
 }
 
-gfxFont*
+UniquePtr<gfxFont>
 gfxGDIFont::CopyWithAntialiasOption(AntialiasOption anAAOption)
 {
-    return new gfxGDIFont(static_cast<GDIFontEntry*>(mFontEntry.get()),
-                          &mStyle, mNeedsBold, anAAOption);
+    auto entry = static_cast<GDIFontEntry*>(mFontEntry.get());
+    return MakeUnique<gfxGDIFont>(entry, &mStyle, mNeedsBold, anAAOption);
 }
 
 bool
diff --git a/gfx/thebes/gfxGDIFont.h b/gfx/thebes/gfxGDIFont.h
index 9d8ac9552437..1e0e4a25339f 100644
--- a/gfx/thebes/gfxGDIFont.h
+++ b/gfx/thebes/gfxGDIFont.h
@@ -45,7 +45,7 @@ public:
                                uint16_t aOrientation) override;
 
     /* required for MathML to suppress effects of ClearType "padding" */
-    virtual gfxFont*
+    mozilla::UniquePtr<gfxFont>
     CopyWithAntialiasOption(AntialiasOption anAAOption) override;
 
     // If the font has a cmap table, we handle it purely with harfbuzz;