change asABitmap to isABitmap on shader

src/core/SkColorShader.h

 /*
  * Copyright 2007 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 SkColorShader_DEFINED
 #define SkColorShader_DEFINED
 
@@ skipping 29 matching lines @@
         void shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) override;
 
     private:
         SkPMColor   fPMColor;
         uint32_t    fFlags;
         uint16_t    fColor16;
 
         typedef SkShader::Context INHERITED;
     };
 
-    // we return false for this, use asAGradient
-    virtual BitmapType asABitmap(SkBitmap* outTexture,
-                                 SkMatrix* outMatrix,
-                                 TileMode xy[2]) const override;
-
     GradientType asAGradient(GradientInfo* info) const override;
 
     bool asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix& viewM,
                              const SkMatrix*, GrColor*, GrProcessorDataManager*,
                              GrFragmentProcessor**) const override;
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkColorShader)
 
 protected:
     SkColorShader(SkReadBuffer&);
     void flatten(SkWriteBuffer&) const override;
     Context* onCreateContext(const ContextRec&, void* storage) const override;
     bool onAsLuminanceColor(SkColor* lum) const override {
         *lum = fColor;
         return true;
     }
 
 private:
     SkColor fColor;
 
     typedef SkShader INHERITED;
 };
 
 #endif