add applyFilter() to SkImage

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 25 matching lines @@
     }
 
     bool getROPixels(SkBitmap*) const override;
     GrTexture* asTextureRef(GrContext* ctx, const GrTextureParams& params) const override;
     SkImage* onNewSubset(const SkIRect&) const override;
 
     GrTexture* peekTexture() const override { return fTexture; }
     bool isOpaque() const override;
     bool onReadPixels(const SkImageInfo&, void* dstPixels, size_t dstRowBytes,
                       int srcX, int srcY) const override;
+    SkImage* onApplyFilter(SkImageFilter*, SkIPoint* offset,
+                           bool forceResultToOriginalSize) const override;
+
+    SkSurface* onNewSurface(const SkImageInfo& info) const override {
+        return SkSurface::NewRenderTarget(fTexture->getContext(), SkSurface::kNo_Budgeted, info);
+    }
 
 private:
     SkAutoTUnref<GrTexture>     fTexture;
     const SkAlphaType           fAlphaType;
     const SkSurface::Budgeted   fBudgeted;
     mutable SkAtomic<bool>      fAddedRasterVersionToCache;
 
 
     typedef SkImage_Base INHERITED;
 };
 
 #endif