It is dangerous to ignore SkRect::intersect's return value

gm/offsetimagefilter.cpp

Index: gm/offsetimagefilter.cpp
diff --git a/gm/offsetimagefilter.cpp b/gm/offsetimagefilter.cpp
index 7fcbe0a04db973ec8355bdac280bef6fc92ab0e9..3dafed8823ef498a798a99d8b59797d511e6e55d 100644
--- a/gm/offsetimagefilter.cpp
+++ b/gm/offsetimagefilter.cpp
@@ -82,8 +82,9 @@ protected:
         scaleMatrix.setScale(scale, scale);
         SkRect cropRectFloat;
         scaleMatrix.mapRect(&cropRectFloat, SkRect::Make(cropRect));
-        clipRect.intersect(cropRectFloat);
-        canvas->drawRect(clipRect, strokePaint);
+        if (clipRect.intersect(cropRectFloat)) {
+            canvas->drawRect(clipRect, strokePaint);
+        }
     }
 
     virtual void onDraw(SkCanvas* canvas) {