--- a/gfx/2d/2D.h
+++ b/gfx/2d/2D.h
@@ -364,22 +364,16 @@ public:
 
   /* [DEPRECATED]
    * Stride of the surface, distance in bytes between the start of the image
    * data belonging to row y and row y+1. This may be negative.
    * Can return 0 if there was OOM allocating surface data.
    */
   virtual int32_t Stride() = 0;
 
-  /*
-   * This function is called after modifying the data on the source surface
-   * directly through the data pointer.
-   */
-  virtual void MarkDirty() {}
-
   virtual bool Map(MapType, MappedSurface *aMappedSurface)
   {
     aMappedSurface->mData = GetData();
     aMappedSurface->mStride = Stride();
     mIsMapped = true;
     return true;
   }
 

--- a/gfx/2d/DataSourceSurfaceWrapper.h
+++ b/gfx/2d/DataSourceSurfaceWrapper.h
@@ -22,17 +22,16 @@ public:
 
   virtual SurfaceType GetType() const MOZ_OVERRIDE { return SurfaceType::DATA; }
 
   virtual uint8_t *GetData() MOZ_OVERRIDE { return mSurface->GetData(); }
   virtual int32_t Stride() MOZ_OVERRIDE { return mSurface->Stride(); }
   virtual IntSize GetSize() const MOZ_OVERRIDE { return mSurface->GetSize(); }
   virtual SurfaceFormat GetFormat() const MOZ_OVERRIDE { return mSurface->GetFormat(); }
   virtual bool IsValid() const MOZ_OVERRIDE { return mSurface->IsValid(); }
-  virtual void MarkDirty() { mSurface->MarkDirty(); }
 
 private:
   RefPtr<DataSourceSurface> mSurface;
 };
 
 }
 }