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/tests/PaintImageFilterTest.cpp b/tests/PaintImageFilterTest.cpp
index 0365336..7ca7bc3 100644
--- a/tests/PaintImageFilterTest.cpp
+++ b/tests/PaintImageFilterTest.cpp
@@ -5,6 +5,7 @@
  * found in the LICENSE file.
  */
 
+#include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkGradientShader.h"
 #include "SkPaintImageFilter.h"