Add a fix for a spurious assert in SkMatrixConvolutionImageFilter.

tests/ImageFilterTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBicubicImageFilter.h"
 #include "SkBitmap.h"
 #include "SkBitmapDevice.h"
@@ skipping 354 matching lines @@
                 break;
             }
         }
     }
 
     for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
         SkSafeUnref(filters[i].fFilter);
     }
 }
 
+DEF_TEST(ImageFilterMatrixConvolution, reporter) {
+    // Check that a 1x3 filter does not cause a spurious assert.
+    SkScalar kernel[3] = {
+        SkIntToScalar( 1), SkIntToScalar( 1), SkIntToScalar( 1),
+    };
+    SkISize kernelSize = SkISize::Make(1, 3);
+    SkScalar gain = SK_Scalar1, bias = 0;
+    SkIPoint kernelOffset = SkIPoint::Make(0, 0);
+
+    SkAutoTUnref<SkImageFilter> filter(
+        SkMatrixConvolutionImageFilter::Create(
+            kernelSize, kernel, gain, bias, kernelOffset,
+            SkMatrixConvolutionImageFilter::kRepeat_TileMode, false));
+
+    SkBitmap result;
+    int width = 16, height = 16;
+    result.allocN32Pixels(width, height);
+    SkCanvas canvas(result);
+    canvas.clear(0);
+
+    SkPaint paint;
+    paint.setImageFilter(filter);
+    SkRect rect = SkRect::MakeWH(width, height);
+    canvas.drawRect(rect, paint);
+}
+
 DEF_TEST(ImageFilterCropRect, reporter) {
     SkBitmap temp;
     temp.allocN32Pixels(100, 100);
     SkBitmapDevice device(temp);
     test_crop_rects(&device, reporter);
 }
 
 DEF_TEST(ImageFilterMatrixTest, reporter) {
     SkBitmap temp;
     temp.allocN32Pixels(100, 100);
@@ skipping 168 matching lines @@
 }
 
 DEF_GPUTEST(XfermodeImageFilterCroppedInputGPU, reporter, factory) {
     GrContext* context = factory->get(static_cast<GrContextFactory::GLContextType>(0));
     SkAutoTUnref<SkGpuDevice> device(SkGpuDevice::Create(context,
                                                          SkImageInfo::MakeN32Premul(1, 1),
                                                          0));
     test_xfermode_cropped_input(device, reporter);
 }
 #endif