scaling API on SkPixmap

BUG=skia:4481

Review URL: https://codereview.chromium.org/1463373002
diff --git a/src/image/SkImage_Raster.cpp b/src/image/SkImage_Raster.cpp
index 9c90ba9..977dc01 100644
--- a/src/image/SkImage_Raster.cpp
+++ b/src/image/SkImage_Raster.cpp
@@ -66,10 +66,10 @@
     SkImage_Raster(const SkImageInfo&, SkData*, size_t rb, SkColorTable*);
     virtual ~SkImage_Raster();
 
-    bool onReadPixels(const SkImageInfo&, void*, size_t, int srcX, int srcY) const override;
+    bool onReadPixels(const SkImageInfo&, void*, size_t, int srcX, int srcY, CachingHint) const override;
     const void* onPeekPixels(SkImageInfo*, size_t* /*rowBytes*/) const override;
     SkData* onRefEncoded() const override;
-    bool getROPixels(SkBitmap*) const override;
+    bool getROPixels(SkBitmap*, CachingHint) const override;
     GrTexture* asTextureRef(GrContext*, const GrTextureParams&) const override;
     SkImage* onNewSubset(const SkIRect&) const override;
 
@@ -135,7 +135,7 @@
 SkImage_Raster::~SkImage_Raster() {}
 
 bool SkImage_Raster::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
-                                  int srcX, int srcY) const {
+                                  int srcX, int srcY, CachingHint) const {
     SkBitmap shallowCopy(fBitmap);
     return shallowCopy.readPixels(dstInfo, dstPixels, dstRowBytes, srcX, srcY);
 }
@@ -162,7 +162,7 @@
     return nullptr;
 }
 
-bool SkImage_Raster::getROPixels(SkBitmap* dst) const {
+bool SkImage_Raster::getROPixels(SkBitmap* dst, CachingHint) const {
     *dst = fBitmap;
     return true;
 }