Make filters use SkImage instead of SkBitmap

src/core/SkDeviceImageFilterProxy.h

Index: src/core/SkDeviceImageFilterProxy.h
diff --git a/src/core/SkDeviceImageFilterProxy.h b/src/core/SkDeviceImageFilterProxy.h
index 0ae686d877df4b81eb0b2c68bfe566a91d96af5c..3bff1d0fbf50b31da6c58db5c458ba6599108546 100644
--- a/src/core/SkDeviceImageFilterProxy.h
+++ b/src/core/SkDeviceImageFilterProxy.h
@@ -31,9 +31,9 @@ public:
     bool canHandleImageFilter(const SkImageFilter* filter) SK_OVERRIDE {
         return fDevice->canHandleImageFilter(filter);
     }
-    virtual bool filterImage(const SkImageFilter* filter, const SkBitmap& src,
+    virtual bool filterImage(const SkImageFilter* filter, const SkImage* src,
                              const SkImageFilter::Context& ctx,
-                             SkBitmap* result, SkIPoint* offset) SK_OVERRIDE {
+                             SkAutoTUnref<const SkImage>& result, SkIPoint* offset) SK_OVERRIDE {
         return fDevice->filterImage(filter, src, ctx, result, offset);
     }