diff --git a/tests/WritePixelsTest.cpp b/tests/WritePixelsTest.cpp
index 688aa5d..5911b80 100644
--- a/tests/WritePixelsTest.cpp
+++ b/tests/WritePixelsTest.cpp
@@ -10,6 +10,7 @@
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkDevice.h"
+#include "SkMathPriv.h"
 #include "SkRegion.h"
 #if SK_SUPPORT_GPU
 #include "SkGpuDevice.h"