Plumb through out_row byte length so we can assert we stay underneath it.

src/core/SkConvolver.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SK_CONVOLVER_H
 #define SK_CONVOLVER_H
 
 #include "SkSize.h"
 #include "SkTypes.h"
 #include "SkTArray.h"
@@ skipping 135 matching lines @@
 typedef void (*SkConvolveVertically_pointer)(
     const SkConvolutionFilter1D::ConvolutionFixed* filterValues,
     int filterLength,
     unsigned char* const* sourceDataRows,
     int pixelWidth,
     unsigned char* outRow,
     bool hasAlpha);
 typedef void (*SkConvolve4RowsHorizontally_pointer)(
     const unsigned char* srcData[4],
     const SkConvolutionFilter1D& filter,
-    unsigned char* outRow[4]);
+    unsigned char* outRow[4],
+    size_t outRowBytes);
 typedef void (*SkConvolveHorizontally_pointer)(
     const unsigned char* srcData,
     const SkConvolutionFilter1D& filter,
     unsigned char* outRow,
     bool hasAlpha);
 typedef void (*SkConvolveFilterPadding_pointer)(
     SkConvolutionFilter1D* filter);
 
 struct SkConvolutionProcs {
   // This is how many extra pixels may be read by the
@@ skipping 29 matching lines @@
     int sourceByteRowStride,
     bool sourceHasAlpha,
     const SkConvolutionFilter1D& xfilter,
     const SkConvolutionFilter1D& yfilter,
     int outputByteRowStride,
     unsigned char* output,
     const SkConvolutionProcs&,
     bool useSimdIfPossible);
 
 #endif  // SK_CONVOLVER_H