Added missing validation

src/effects/SkMatrixConvolutionImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkMatrixConvolutionImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
@@ skipping 49 matching lines @@
     uint32_t uniqueID) {
     if (kernelSize.width() < 1 || kernelSize.height() < 1) {
         return NULL;
     }
     if (gMaxKernelSize / kernelSize.fWidth < kernelSize.fHeight) {
         return NULL;
     }
     if (!kernel) {
         return NULL;
     }
+    if ((kernelOffset.fX < 0) || (kernelOffset.fX >= kernelSize.fWidth) ||
+        (kernelOffset.fY < 0) || (kernelOffset.fY >= kernelSize.fHeight)) {
+        return NULL;
+    }
     return SkNEW_ARGS(SkMatrixConvolutionImageFilter, (kernelSize, kernel, gain, bias,
                                                        kernelOffset, tileMode, convolveAlpha,
                                                        input, cropRect, uniqueID));
 }
 
 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 static bool tile_mode_is_valid(SkMatrixConvolutionImageFilter::TileMode tileMode) {
     switch (tileMode) {
         case SkMatrixConvolutionImageFilter::kClamp_TileMode:
         case SkMatrixConvolutionImageFilter::kRepeat_TileMode:
@@ skipping 322 matching lines @@
                                             fKernelSize,
                                             fKernel,
                                             fGain,
                                             fBias,
                                             fKernelOffset,
                                             convert_tilemodes(fTileMode),
                                             fConvolveAlpha);
     return true;
 }
 #endif