Add SkSourceGammaTreatment enum so we know how to create mips

src/core/SkPictureShader.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 SkPictureShader_DEFINED
 #define SkPictureShader_DEFINED
 
@@ skipping 13 matching lines @@
     static sk_sp<SkShader> Make(sk_sp<SkPicture>, TileMode, TileMode, const SkMatrix*,
                                 const SkRect*);
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPictureShader)
 
 #if SK_SUPPORT_GPU
     const GrFragmentProcessor* asFragmentProcessor(GrContext*,
                                                    const SkMatrix& viewM,
                                                    const SkMatrix*,
-                                                   SkFilterQuality) const override;
+                                                   SkFilterQuality,
+                                                   SkSourceGammaTreatment) const override;
 #endif
 
 protected:
     SkPictureShader(SkReadBuffer&);
     void flatten(SkWriteBuffer&) const override;
     size_t onContextSize(const ContextRec&) const override;
     Context* onCreateContext(const ContextRec&, void* storage) const override;
 
 private:
     SkPictureShader(sk_sp<SkPicture>, TileMode, TileMode, const SkMatrix*, const SkRect*);
@@ skipping 25 matching lines @@
         SkShader::Context*  fBitmapShaderContext;
         void*               fBitmapShaderContextStorage;
 
         typedef SkShader::Context INHERITED;
     };
 
     typedef SkShader INHERITED;
 };
 
 #endif // SkPictureShader_DEFINED