Make degenerate kernel in fill_in_2D_gaussian_kernel sum to 1

Bug: 836113
Change-Id: I1b2ed1d67648163571df6c497365d2a293b3b589
Reviewed-on: https://skia-review.googlesource.com/126020
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/gpu/effects/GrMatrixConvolutionEffect.cpp b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
index 56b012afe5..f7e6675c80 100644
--- a/src/gpu/effects/GrMatrixConvolutionEffect.cpp
+++ b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
@@ -220,9 +220,11 @@ static void fill_in_2D_gaussian_kernel(float* kernel, int width, int height,
 
     if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero) ||
         SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero)) {
+        SkASSERT(3 == width && 3 == height);
         for (int i = 0; i < width * height; ++i) {
             kernel[i] = 0.0f;
         }
+        kernel[4] = 1.0f;
         return;
     }