--- a/layout/svg/moz.build
+++ b/layout/svg/moz.build
@@ -17,16 +17,17 @@ if CONFIG['ENABLE_TESTS']:
 
 EXPORTS += [
     'nsFilterInstance.h',
     'nsSVGEffects.h',
     'nsSVGFilterInstance.h',
     'nsSVGForeignObjectFrame.h',
     'nsSVGImageFrame.h',
     'nsSVGIntegrationUtils.h',
+    'nsSVGUseFrame.h',
     'nsSVGUtils.h',
     'SVGImageContext.h',
 ]
 
 EXPORTS.mozilla += [
     'SVGContextPaint.h',
 ]
 

--- a/layout/svg/nsSVGUseFrame.cpp
+++ b/layout/svg/nsSVGUseFrame.cpp
@@ -1,70 +1,21 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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/. */
 
-// Keep in (case-insensitive) order:
-#include "nsIAnonymousContentCreator.h"
-#include "nsSVGEffects.h"
-#include "nsSVGGFrame.h"
+#include "nsSVGUseFrame.h"
+
 #include "mozilla/dom/SVGUseElement.h"
 #include "nsContentList.h"
+#include "nsSVGEffects.h"
 
 using namespace mozilla::dom;
 
-class nsSVGUseFrame final
-  : public nsSVGGFrame
-  , public nsIAnonymousContentCreator
-{
-  friend nsIFrame*
-  NS_NewSVGUseFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
-
-protected:
-  explicit nsSVGUseFrame(nsStyleContext* aContext)
-    : nsSVGGFrame(aContext, kClassID)
-    , mHasValidDimensions(true)
-  {}
-
-public:
-  NS_DECL_QUERYFRAME
-  NS_DECL_FRAMEARENA_HELPERS(nsSVGUseFrame)
-
-  // nsIFrame interface:
-  virtual void Init(nsIContent*       aContent,
-                    nsContainerFrame* aParent,
-                    nsIFrame*         aPrevInFlow) override;
-
-  virtual nsresult  AttributeChanged(int32_t         aNameSpaceID,
-                                     nsIAtom*        aAttribute,
-                                     int32_t         aModType) override;
-
-  virtual void DestroyFrom(nsIFrame* aDestructRoot) override;
-
-#ifdef DEBUG_FRAME_DUMP
-  virtual nsresult GetFrameName(nsAString& aResult) const override
-  {
-    return MakeFrameName(NS_LITERAL_STRING("SVGUse"), aResult);
-  }
-#endif
-
-  // nsSVGDisplayableFrame interface:
-  virtual void ReflowSVG() override;
-  virtual void NotifySVGChanged(uint32_t aFlags) override;
-
-  // nsIAnonymousContentCreator
-  virtual nsresult CreateAnonymousContent(nsTArray<ContentInfo>& aElements) override;
-  virtual void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
-                                        uint32_t aFilter) override;
-
-private:
-  bool mHasValidDimensions;
-};
-
 //----------------------------------------------------------------------
 // Implementation
 
 nsIFrame*
 NS_NewSVGUseFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 {
   return new (aPresShell) nsSVGUseFrame(aContext);
 }

new file mode 100644
--- /dev/null
+++ b/layout/svg/nsSVGUseFrame.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef __NS_SVGUSEFRAME_H__
+#define __NS_SVGUSEFRAME_H__
+
+// Keep in (case-insensitive) order:
+#include "nsIAnonymousContentCreator.h"
+#include "nsSVGGFrame.h"
+
+class nsSVGUseFrame final
+  : public nsSVGGFrame
+  , public nsIAnonymousContentCreator
+{
+  friend nsIFrame* NS_NewSVGUseFrame(nsIPresShell* aPresShell,
+                                     nsStyleContext* aContext);
+
+protected:
+  explicit nsSVGUseFrame(nsStyleContext* aContext)
+    : nsSVGGFrame(aContext, kClassID)
+    , mHasValidDimensions(true)
+  {
+  }
+
+public:
+  NS_DECL_QUERYFRAME
+  NS_DECL_FRAMEARENA_HELPERS(nsSVGUseFrame)
+
+  // nsIFrame interface:
+  void Init(nsIContent* aContent,
+            nsContainerFrame* aParent,
+            nsIFrame* aPrevInFlow) override;
+
+  nsresult AttributeChanged(int32_t aNameSpaceID,
+                            nsIAtom* aAttribute,
+                            int32_t aModType) override;
+
+  void DestroyFrom(nsIFrame* aDestructRoot) override;
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const override
+  {
+    return MakeFrameName(NS_LITERAL_STRING("SVGUse"), aResult);
+  }
+#endif
+
+  // nsSVGDisplayableFrame interface:
+  void ReflowSVG() override;
+  void NotifySVGChanged(uint32_t aFlags) override;
+
+  // nsIAnonymousContentCreator
+  nsresult CreateAnonymousContent(nsTArray<ContentInfo>& aElements) override;
+  void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
+                                uint32_t aFilter) override;
+
+private:
+  bool mHasValidDimensions;
+};
+
+#endif // __NS_SVGUSEFRAME_H__