add SkImage::newSurface

include/core/SkImage.h

Index: include/core/SkImage.h
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 4e016348559b0f32358a710269724dedba545fd4..5b5a27f5fb9dbc8ca2d64f75ecdf87cfdef0df3c 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -18,6 +18,8 @@ class SkData;
 class SkCanvas;
 class SkImageGenerator;
 class SkPaint;
+class SkSurface;
+class SkSurfaceProps;
 class GrContext;
 class GrTexture;
 
@@ -92,6 +94,12 @@ public:
     SkData* encode(SkImageEncoder::Type t = SkImageEncoder::kPNG_Type,
                    int quality = 80) const;
 
+    /**
+     *  Return a new surface that is compatible with this image's internal representation
+     *  (e.g. raster or gpu).
+     */
+    SkSurface* newSurface(const SkImageInfo&, const SkSurfaceProps&) const;
+
 protected:
     SkImage(int width, int height) :
         fWidth(width),