Fix for SkMatrixConvolutionImageFilter with large borders.

src/effects/SkMatrixConvolutionImageFilter.cpp

Index: src/effects/SkMatrixConvolutionImageFilter.cpp
diff --git a/src/effects/SkMatrixConvolutionImageFilter.cpp b/src/effects/SkMatrixConvolutionImageFilter.cpp
index be1dcb4ce970e9ad859bcc6f8fffb4fe9bb795c8..f6bc6a1f1f47c30db1a0093cfc40ce4d829e20bf 100644
--- a/src/effects/SkMatrixConvolutionImageFilter.cpp
+++ b/src/effects/SkMatrixConvolutionImageFilter.cpp
@@ -151,9 +151,10 @@ public:
 template<class PixelFetcher, bool convolveAlpha>
 void SkMatrixConvolutionImageFilter::filterPixels(const SkBitmap& src,
                                                   SkBitmap* result,
-                                                  const SkIRect& rect,
+                                                  const SkIRect& r,
                                                   const SkIRect& bounds) const {
-    if (rect.isEmpty()) {
+    SkIRect rect(r);
+    if (!rect.intersect(bounds)) {
         return;
     }
     for (int y = rect.fTop; y < rect.fBottom; ++y) {