initial preroll api

include/core/SkImage.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImage_DEFINED
 #define SkImage_DEFINED
 
@@ skipping 113 matching lines @@
 
     /**
      *  Return a new surface that is compatible with this image's internal representation
      *  (e.g. raster or gpu).
      *
      *  If no surfaceprops are specified, the image will attempt to match the props of when it
      *  was created (if it came from a surface).
      */
     SkSurface* newSurface(const SkImageInfo&, const SkSurfaceProps* = NULL) const;
 
+    void preroll() const;
+
     const char* toString(SkString*) const;
 
     /**
      *  Return an image that is a rescale of this image (using newWidth, newHeight).
      *
      *  If subset is NULL, then the entire original image is used as the src for the scaling.
      *  If subset is not NULL, then it specifies subset of src-pixels used for scaling. If
      *  subset extends beyond the bounds of the original image, then NULL is returned.
      *
      *  Notes:
@@ skipping 37 matching lines @@
      *  Draw the image, cropped to the src rect, to the dst rect of a canvas.
      *  If src is larger than the bounds of the image, the rest of the image is
      *  filled with transparent black pixels.
      *
      *  See SkCanvas::drawBitmapRectToRect for similar behavior.
      */
     void drawRect(SkCanvas*, const SkRect* src, const SkRect& dst, const SkPaint*) const;
 };
 
 #endif