Enhance SkDropShadowImageFilter to support separate X & Y sigmas, and crop rect.

include/effects/SkDropShadowImageFilter.h

Index: include/effects/SkDropShadowImageFilter.h
diff --git a/include/effects/SkDropShadowImageFilter.h b/include/effects/SkDropShadowImageFilter.h
index 501df7cf7f6c7816ac40f42eadcae587f1e67606..5a58a0a06a4c6bd867639f2349620eb55f03e5ef 100644
--- a/include/effects/SkDropShadowImageFilter.h
+++ b/include/effects/SkDropShadowImageFilter.h
@@ -12,6 +12,7 @@
 class SK_API SkDropShadowImageFilter : public SkImageFilter {
 public:
     SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigma, SkColor, SkImageFilter* input = NULL);
+    SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigmaX, SkScalar sigmaY, SkColor, SkImageFilter* input = NULL, const CropRect* cropRect = NULL);

[reed1, 2013/11/26 20:58:39]

At some point we should probably harden up our default arguments, and require
more of them. However, this is not the only case, so lgtm

     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDropShadowImageFilter)
 
 protected:
@@ -20,7 +21,7 @@ protected:
     virtual bool onFilterImage(Proxy*, const SkBitmap& source, const SkMatrix&, SkBitmap* result, SkIPoint* loc) SK_OVERRIDE;
 
 private:
-    SkScalar fDx, fDy, fSigma;
+    SkScalar fDx, fDy, fSigmaX, fSigmaY;
     SkColor fColor;
     typedef SkImageFilter INHERITED;
 };