Make filters use SkImage instead of SkBitmap

src/gpu/SkGpuDevice.h

Index: src/gpu/SkGpuDevice.h
diff --git a/src/gpu/SkGpuDevice.h b/src/gpu/SkGpuDevice.h
index d166abc290ea184b3e48b0c98138f3117cc3f193..9c64662538858c889b186b6daf961e5b96e81b8c 100644
--- a/src/gpu/SkGpuDevice.h
+++ b/src/gpu/SkGpuDevice.h
@@ -126,13 +126,13 @@ public:
     const SkBitmap& onAccessBitmap() SK_OVERRIDE;
 
     bool canHandleImageFilter(const SkImageFilter*) SK_OVERRIDE;
-    virtual bool filterImage(const SkImageFilter*, const SkBitmap&,
+    virtual bool filterImage(const SkImageFilter*, const SkImage*,
                              const SkImageFilter::Context&,
-                             SkBitmap*, SkIPoint*) SK_OVERRIDE;
+                             SkAutoTUnref<const SkImage>&, SkIPoint*) SK_OVERRIDE;
 
     bool filterTexture(GrContext*, GrTexture*, const SkImageFilter*,
                        const SkImageFilter::Context&,
-                       SkBitmap* result, SkIPoint* offset);
+                       SkAutoTUnref<const SkImage>& result, SkIPoint* offset);
 
 protected:
     bool onReadPixels(const SkImageInfo&, void*, size_t, int, int) SK_OVERRIDE;