Add class GrGLTextureRenderTarget for GL texture/rendertarget objects

src/gpu/GrOptDrawState.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrOptDrawState_DEFINED
 #define GrOptDrawState_DEFINED
 
@@ skipping 151 matching lines @@
 
     ///////////////////////////////////////////////////////////////////////////
     /// @name Render Target
     ////
 
     /**
      * Retrieves the currently set render-target.
      *
      * @return    The currently set render target.
      */
-    GrRenderTarget* getRenderTarget() const {
-        return static_cast<GrRenderTarget*>(fRenderTarget.getResource());
-    }
+    GrRenderTarget* getRenderTarget() const { return fRenderTarget.get(); }
 
     /// @}
 
     ///////////////////////////////////////////////////////////////////////////
     /// @name Stencil
     ////
 
     const GrStencilSettings& getStencil() const { return fStencilSettings; }
 
     /// @}
@@ skipping 208 matching lines @@
 
     GrProgramDesc fDesc;
 
     typedef SkRefCnt INHERITED;
 };
 
 GR_MAKE_BITFIELD_OPS(GrOptDrawState::BlendOptFlags);
 
 #endif