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 909e60d2df4656b30942c936e96ae079c04df4d7..3e3f401d12a9e7f786cceaaadfaaa5ad648d14cf 100644
--- a/src/core/SkDeviceImageFilterProxy.h
+++ b/src/core/SkDeviceImageFilterProxy.h
@@ -28,9 +28,9 @@ 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);
     }