added support for half input variables in SkSL fragment processors

Bug: skia:
Change-Id: Iccdd98d9949c2a5f3da650282f520c65f2bb5094
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/205350
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Jonathan Backer <backer@chromium.org>
diff --git a/gm/runtimecolorfilter.cpp b/gm/runtimecolorfilter.cpp
index efee4a8..89252b6 100644
--- a/gm/runtimecolorfilter.cpp
+++ b/gm/runtimecolorfilter.cpp
@@ -15,11 +15,11 @@
 #include "gm.h"
 
 const char* SKSL_TEST_SRC = R"(
-    in uniform float b;
+    layout(ctype=float) in uniform half b;
 
     void main(inout half4 color) {
         color.rg = color.gr;
-        color.b = half(b);
+        color.b = b;
     }
 )";