Initial error handling code

src/effects/SkMagnifierImageFilter.cpp

Index: src/effects/SkMagnifierImageFilter.cpp
diff --git a/src/effects/SkMagnifierImageFilter.cpp b/src/effects/SkMagnifierImageFilter.cpp
index e3d6efd4372e5d74a945bc61a6ef36341c6805b3..a3d51e618725a39ae36f95bdba498a129cd33cac 100644
--- a/src/effects/SkMagnifierImageFilter.cpp
+++ b/src/effects/SkMagnifierImageFilter.cpp
@@ -9,6 +9,7 @@
 #include "SkMagnifierImageFilter.h"
 #include "SkColorPriv.h"
 #include "SkFlattenableBuffers.h"
+#include "SkValidationUtils.h"
 
 ////////////////////////////////////////////////////////////////////////////////
 #if SK_SUPPORT_GPU
@@ -236,6 +237,8 @@ SkMagnifierImageFilter::SkMagnifierImageFilter(SkFlattenableReadBuffer& buffer)
     float height = buffer.readScalar();
     fSrcRect = SkRect::MakeXYWH(x, y, width, height);
     fInset = buffer.readScalar();
+
+    buffer.validate(SkIsValidRect(fSrcRect) && SkScalarIsFinite(fInset));
 }
 
 // FIXME:  implement single-input semantics