add SkImage::newSurface

src/image/SkImage_Base.h

Index: src/image/SkImage_Base.h
diff --git a/src/image/SkImage_Base.h b/src/image/SkImage_Base.h
index 4ff6a25965166beca7f6aef96008936f8e8929fd..a82f1f425275a0123c3fc870f86ccdc8fb67ee1b 100644
--- a/src/image/SkImage_Base.h
+++ b/src/image/SkImage_Base.h
@@ -17,6 +17,7 @@ public:
     virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) const = 0;
     virtual void onDrawRect(SkCanvas*, const SkRect* src,
                                   const SkRect& dst, const SkPaint*) const = 0;
+    virtual SkSurface* onNewSurface(const SkImageInfo&, const SkSurfaceProps&) const = 0;
 
     // Default impl calls onDraw
     virtual bool onReadPixels(SkBitmap*, const SkIRect& subset) const;
@@ -34,6 +35,7 @@ public:
     virtual SkShader* onNewShader(SkShader::TileMode,
                                   SkShader::TileMode,
                                   const SkMatrix* localMatrix) const { return NULL; };
+
 private:
     typedef SkImage INHERITED;
 };