IWYU -- SkShader.h

Bug: skia:
Change-Id: I57bffc14c4888627a22158e35f3ac3b762138f02
Reviewed-on: https://skia-review.googlesource.com/98520
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/samplecode/SampleHairline.cpp b/samplecode/SampleHairline.cpp
index 0adc9c3..51fff8d 100644
--- a/samplecode/SampleHairline.cpp
+++ b/samplecode/SampleHairline.cpp
@@ -8,6 +8,7 @@
 #include "SampleCode.h"
 #include "SkAnimTimer.h"
 #include "SkView.h"
+#include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkCornerPathEffect.h"
 #include "SkGradientShader.h"