Add helper for creating a SkSurface from a client created texture.

include/core/SkSurface.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 SkSurface_DEFINED
 #define SkSurface_DEFINED
 
@@ skipping 75 matching lines @@
     }
 
     /**
      *  Return a new surface using the specified render target.
      */
     static SkSurface* NewRenderTargetDirect(GrRenderTarget*, const SkSurfaceProps*);
     
     static SkSurface* NewRenderTargetDirect(GrRenderTarget* target) {
         return NewRenderTargetDirect(target, NULL);
     }
+
+    /**
+     *  Used to wrap a pre-existing backend 3D API texture in a SkSurface. The kRenderTarget flag
+     *  must be set on GrBackendTextureDesc for this to succeed.
+     */
+    static SkSurface* NewWrappedRenderTarget(GrContext*, GrBackendTextureDesc,
+                                             const SkSurfaceProps*);
     
     /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface.
      */
     static SkSurface* NewRenderTarget(GrContext*, Budgeted, const SkImageInfo&, int sampleCount,
                                       const SkSurfaceProps* = NULL);
 
     static SkSurface* NewRenderTarget(GrContext* gr, Budgeted b, const SkImageInfo& info) {
         return NewRenderTarget(gr, b, info, 0, NULL);
@@ skipping 123 matching lines @@
 private:
     const SkSurfaceProps fProps;
     const int            fWidth;
     const int            fHeight;
     uint32_t             fGenerationID;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif