Make specialized SrcOver XPFactory

include/core/SkXfermode.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkXfermode_DEFINED
@@ skipping 191 matching lines @@
      */
     virtual bool asFragmentProcessor(const GrFragmentProcessor** output,
                                      const GrFragmentProcessor* dst) const;
 
     /** A subclass may implement this factory function to work with the GPU backend. It is legal
         to call this with xpf NULL to simply test the return value. If xpf is non-NULL then the
         xfermode may optionally allocate a factory to return to the caller as *xpf. The caller
         will install it and own a ref to it. Since the xfermode may or may not assign *xpf, the
         caller should set *xpf to NULL beforehand. XferProcessors cannot use a background texture.
      */
-    virtual bool asXPFactory(GrXPFactory** xpf) const;
+    virtual bool asXPFactory(const GrXPFactory** xpf) const;
 
     /** Returns true if the xfermode can be expressed as an xfer processor factory (xpFactory).
         This helper calls the asXPFactory() virtual. If the xfermode is NULL, it is treated as
         kSrcOver_Mode. It is legal to call this with xpf param NULL to simply test the return value.
      */
-    static bool AsXPFactory(SkXfermode*, GrXPFactory**);
+    static bool AsXPFactory(SkXfermode*, const GrXPFactory**);
 
     SK_TO_STRING_PUREVIRT()
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
     SK_DEFINE_FLATTENABLE_TYPE(SkXfermode)
 
 protected:
     SkXfermode() {}
     /** The default implementation of xfer32/xfer16/xferA8 in turn call this
         method, 1 color at a time (upscaled to a SkPMColor). The default
         implementation of this method just returns dst. If performance is
         important, your subclass should override xfer32/xfer16/xferA8 directly.
 
         This method will not be called directly by the client, so it need not
         be implemented if your subclass has overridden xfer32/xfer16/xferA8
     */
     virtual SkPMColor xferColor(SkPMColor src, SkPMColor dst) const;
 
 private:
     enum {
         kModeCount = kLastMode + 1
     };
 
     typedef SkFlattenable INHERITED;
 };
 
 #endif