Clean up SkImageFilter constructors.

include/effects/SkMagnifierImageFilter.h

Index: include/effects/SkMagnifierImageFilter.h
diff --git a/include/effects/SkMagnifierImageFilter.h b/include/effects/SkMagnifierImageFilter.h
index b992e282b60b6d459f39e37b457333d9b3ab6c60..3f799d6555f41914dde7f765bb971682f17fb0cf 100644
--- a/include/effects/SkMagnifierImageFilter.h
+++ b/include/effects/SkMagnifierImageFilter.h
@@ -14,14 +14,15 @@
 
 class SK_API SkMagnifierImageFilter : public SkImageFilter {
 public:
-    static SkMagnifierImageFilter* Create(const SkRect& srcRect, SkScalar inset) {
-        return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset));
+    static SkMagnifierImageFilter* Create(const SkRect& srcRect, SkScalar inset,
+                                          SkImageFilter* input = NULL) {
+        return SkNEW_ARGS(SkMagnifierImageFilter, (srcRect, inset, input));
     }
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkMagnifierImageFilter)
 
 protected:
-    SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset);
+    SkMagnifierImageFilter(const SkRect& srcRect, SkScalar inset, SkImageFilter* input);
     explicit SkMagnifierImageFilter(SkReadBuffer& buffer);
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;