IWYU

fissioned from https://skia-review.googlesource.com/c/skia/+/185460

Bug: skia:
Change-Id: I92857df460ffec402101bfa4c90678db889ea9c5
Reviewed-on: https://skia-review.googlesource.com/c/185697
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
diff --git a/samplecode/SampleChineseFling.cpp b/samplecode/SampleChineseFling.cpp
index a556bd6..9f33211 100644
--- a/samplecode/SampleChineseFling.cpp
+++ b/samplecode/SampleChineseFling.cpp
@@ -10,6 +10,7 @@
 #include "sk_tool_utils.h"
 
 #include "SkCanvas.h"
+#include "SkFontMetrics.h"
 #include "SkFontMgr.h"
 #include "SkRandom.h"
 #include "SkTypeface.h"