Added SkComposeShader GPU implementation

include/core/SkComposeShader.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 SkComposeShader_DEFINED
@@ skipping 18 matching lines @@
         @param shaderA  The colors from this shader are seen as the "dst" by the xfermode
         @param shaderB  The colors from this shader are seen as the "src" by the xfermode
         @param mode     The xfermode that combines the colors from the two shaders. If mode
                         is null, then SRC_OVER is assumed.
     */
     SkComposeShader(SkShader* sA, SkShader* sB, SkXfermode* mode = NULL);
     virtual ~SkComposeShader();
 
     size_t contextSize() const override;
 
+#if SK_SUPPORT_GPU
+    const GrFragmentProcessor*  asFragmentProcessor(GrContext*,
+                                                    const SkMatrix& viewM,
+                                                    const SkMatrix* localMatrix,
+                                                    SkFilterQuality,
+                                                    GrProcessorDataManager*) const override;
+#endif
+
     class ComposeShaderContext : public SkShader::Context {
     public:
         // When this object gets destroyed, it will call contextA and contextB's destructor
         // but it will NOT free the memory.
         ComposeShaderContext(const SkComposeShader&, const ContextRec&,
                              SkShader::Context* contextA, SkShader::Context* contextB);
 
         SkShader::Context* getShaderContextA() const { return fShaderContextA; }
         SkShader::Context* getShaderContextB() const { return fShaderContextB; }
 
@@ skipping 25 matching lines @@
 
 private:
     SkShader*   fShaderA;
     SkShader*   fShaderB;
     SkXfermode* fMode;
 
     typedef SkShader INHERITED;
 };
 
 #endif