Make drawImage a virtual on SkDevice

src/image/SkImage_Gpu.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImage_Gpu_DEFINED
 #define SkImage_Gpu_DEFINED
 
 #include "GrTexture.h"
 #include "GrGpuResourcePriv.h"
 #include "SkBitmap.h"
 #include "SkImage_Base.h"
 #include "SkImagePriv.h"
 #include "SkSurface.h"
 
 class SkImage_Gpu : public SkImage_Base {
 public:
     SK_DECLARE_INST_COUNT(SkImage_Gpu)
 
     SkImage_Gpu(const SkBitmap&, int sampleCountForNewSurfaces, SkSurface::Budgeted);
 
-    void onDraw(SkCanvas*, SkScalar x, SkScalar y, const SkPaint*) const override;
-    void onDrawRect(SkCanvas*, const SkRect* src, const SkRect& dst,
-                    const SkPaint*) const override;
     SkSurface* onNewSurface(const SkImageInfo&, const SkSurfaceProps&) const override;
     GrTexture* onGetTexture() const override;
     bool getROPixels(SkBitmap*) const override;
 
     GrTexture* getTexture() const { return fBitmap.getTexture(); }
 
     SkShader* onNewShader(SkShader::TileMode,
                                   SkShader::TileMode,
                                   const SkMatrix* localMatrix) const override;
 
     bool isOpaque() const override;
 
     void applyBudgetDecision() const {
         if (fBudgeted) {
             fBitmap.getTexture()->resourcePriv().makeBudgeted();
         } else {
             fBitmap.getTexture()->resourcePriv().makeUnbudgeted();
         }
     }
 
 private:
     SkBitmap            fBitmap;
     const int           fSampleCountForNewSurfaces;   // 0 if we don't know
     SkSurface::Budgeted fBudgeted;
 
     typedef SkImage_Base INHERITED;
 };
 
 #endif