scaling API on SkPixmap

BUG=skia:4481

Review URL: https://codereview.chromium.org/1463373002
diff --git a/src/image/SkImage_Gpu.h b/src/image/SkImage_Gpu.h
index d5080d7..ff3b12e 100644
--- a/src/image/SkImage_Gpu.h
+++ b/src/image/SkImage_Gpu.h
@@ -35,14 +35,14 @@
         }
     }
 
-    bool getROPixels(SkBitmap*) const override;
+    bool getROPixels(SkBitmap*, CachingHint) 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;
+                      int srcX, int srcY, CachingHint) const override;
     SkImage* onApplyFilter(SkImageFilter*, SkIPoint* offset,
                            bool forceResultToOriginalSize) const override;