--- a/gfx/2d/2D.h
+++ b/gfx/2d/2D.h
@@ -530,16 +530,18 @@ protected:
 class PathBuilder : public PathSink
 {
 public:
   MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(PathBuilder)
   /** Finish writing to the path and return a Path object that can be used for
    * drawing. Future use of the builder results in a crash!
    */
   virtual TemporaryRef<Path> Finish() = 0;
+
+  virtual BackendType GetBackendType() const = 0;
 };
 
 struct Glyph
 {
   uint32_t mIndex;
   Point mPosition;
 };
 

--- a/gfx/2d/PathCG.h
+++ b/gfx/2d/PathCG.h
@@ -42,16 +42,18 @@ public:
                                  const Point &aCP2);
   virtual void Close();
   virtual void Arc(const Point &aOrigin, Float aRadius, Float aStartAngle,
                    Float aEndAngle, bool aAntiClockwise = false);
   virtual Point CurrentPoint() const;
 
   virtual TemporaryRef<Path> Finish();
 
+  virtual BackendType GetBackendType() const { return BackendType::COREGRAPHICS; }
+
 private:
   friend class PathCG;
   friend class ScaledFontMac;
 
   void EnsureActive(const Point &aPoint);
 
   CGMutablePathRef mCGPath;
   Point mCurrentPoint;

--- a/gfx/2d/PathCairo.h
+++ b/gfx/2d/PathCairo.h
@@ -30,16 +30,18 @@ public:
   virtual void QuadraticBezierTo(const Point &aCP1,
                                  const Point &aCP2);
   virtual void Close();
   virtual void Arc(const Point &aOrigin, float aRadius, float aStartAngle,
                    float aEndAngle, bool aAntiClockwise = false);
   virtual Point CurrentPoint() const;
   virtual TemporaryRef<Path> Finish();
 
+  virtual BackendType GetBackendType() const { return BackendType::CAIRO; }
+
 private: // data
   friend class PathCairo;
 
   FillRule mFillRule;
   std::vector<cairo_path_data_t> mPathData;
   // It's easiest to track this here, parsing the path data to find the current
   // point is a little tricky.
   Point mCurrentPoint;

--- a/gfx/2d/PathD2D.h
+++ b/gfx/2d/PathD2D.h
@@ -37,16 +37,18 @@ public:
                                  const Point &aCP2);
   virtual void Close();
   virtual void Arc(const Point &aOrigin, Float aRadius, Float aStartAngle,
                    Float aEndAngle, bool aAntiClockwise = false);
   virtual Point CurrentPoint() const;
 
   virtual TemporaryRef<Path> Finish();
 
+  virtual BackendType GetBackendType() const { return BackendType::DIRECT2D; }
+
   ID2D1GeometrySink *GetSink() { return mSink; }
 
 private:
   friend class PathD2D;
 
   void EnsureActive(const Point &aPoint);
 
   RefPtr<ID2D1GeometrySink> mSink;

--- a/gfx/2d/PathRecording.h
+++ b/gfx/2d/PathRecording.h
@@ -67,16 +67,18 @@ public:
 
   /* Point the current subpath is at - or where the next subpath will start
    * if there is no active subpath.
    */
   virtual Point CurrentPoint() const;
 
   virtual TemporaryRef<Path> Finish();
 
+  virtual BackendType GetBackendType() const { return BackendType::RECORDING; }
+
 private:
   friend class PathRecording;
 
   RefPtr<PathBuilder> mPathBuilder;
   FillRule mFillRule;
   std::vector<PathOp> mPathOps;
 };
 

--- a/gfx/2d/PathSkia.h
+++ b/gfx/2d/PathSkia.h
@@ -31,16 +31,18 @@ public:
   virtual void Close();
   virtual void Arc(const Point &aOrigin, float aRadius, float aStartAngle,
                    float aEndAngle, bool aAntiClockwise = false);
   virtual Point CurrentPoint() const;
   virtual TemporaryRef<Path> Finish();
 
   void AppendPath(const SkPath &aPath);
 
+  virtual BackendType GetBackendType() const { return BackendType::SKIA; }
+
 private:
 
   void SetFillRule(FillRule aFillRule);
 
   SkPath mPath;
   FillRule mFillRule;
 };