Adding more validation

src/effects/SkDropShadowImageFilter.cpp

Index: src/effects/SkDropShadowImageFilter.cpp
diff --git a/src/effects/SkDropShadowImageFilter.cpp b/src/effects/SkDropShadowImageFilter.cpp
index 4fc29bae837016f514bfd93fe08aa83067dcf588..b4d8689f3373fc61427f186ee73bac66b8c8f67e 100644
--- a/src/effects/SkDropShadowImageFilter.cpp
+++ b/src/effects/SkDropShadowImageFilter.cpp
@@ -23,8 +23,8 @@ SkDropShadowImageFilter::SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkSca
 {
 }
 
-SkDropShadowImageFilter::SkDropShadowImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer)
-{
+SkDropShadowImageFilter::SkDropShadowImageFilter(SkFlattenableReadBuffer& buffer)
+ : INHERITED(1, buffer) {
     fDx = buffer.readScalar();
     fDy = buffer.readScalar();
     fSigma = buffer.readScalar();