fix mac build

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2852

Change-Id: I58ba4c8be14b5a40ae94a1f8e69a3c1aa08060d5
Reviewed-on: https://skia-review.googlesource.com/2852
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 1805ca7..233306c 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -37,6 +37,10 @@
 #include "SkReadBuffer.h"
 #include "SkStream.h"
 
+#if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
+#include "SkCGUtils.h"
+#endif
+
 #if SK_SUPPORT_GPU
 #   include "gl/GrGLInterface.h"
 #   include "gl/GrGLUtil.h"