Make filters use SkImage instead of SkBitmap

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
 
@@ skipping 18 matching lines @@
     bool getROPixels(SkBitmap*) const SK_OVERRIDE;
 
     GrTexture* getTexture() const { return fBitmap.getTexture(); }
 
     SkShader* onNewShader(SkShader::TileMode,
                                   SkShader::TileMode,
                                   const SkMatrix* localMatrix) const SK_OVERRIDE;
 
     bool isOpaque() const SK_OVERRIDE;
 
+    size_t getSize() const SK_OVERRIDE { return fBitmap.getSize(); }
+
     void applyBudgetDecision() const {
         if (fBudgeted) {
             fBitmap.getTexture()->cacheAccess().makeBudgeted();
         } else {
             fBitmap.getTexture()->cacheAccess().makeUnbudgeted();
         }
     }
 
 private:
     SkBitmap            fBitmap;
     const int           fSampleCountForNewSurfaces;   // 0 if we don't know
     SkSurface::Budgeted fBudgeted;
 
     typedef SkImage_Base INHERITED;
 };
 
 #endif