Reverse dependency between SkScalar.h and SkFixed.h.

The following are unused in Chromium, Android, Mozilla, and Google3:
 - SkFixedToScalar
 - SkScalarToFixed

The following are additionally unused in Skia:
 - SkStrAppendFixed
 - SkWriteBuffer::writeFixed

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1841123002

Review URL: https://codereview.chromium.org/1841123002
diff --git a/src/core/SkLinearBitmapPipeline_sample.h b/src/core/SkLinearBitmapPipeline_sample.h
index d63509d..9393224 100644
--- a/src/core/SkLinearBitmapPipeline_sample.h
+++ b/src/core/SkLinearBitmapPipeline_sample.h
@@ -8,6 +8,7 @@
 #ifndef SkLinearBitmapPipeline_sampler_DEFINED
 #define SkLinearBitmapPipeline_sampler_DEFINED
 
+#include "SkFixed.h"
 #include "SkLinearBitmapPipeline_core.h"
 #include <array>
 #include <tuple>