added SPIR-V RelaxedPrecision

Bug: skia:5524
Change-Id: I716b6bb8da95acb72ba71d083eb8b40cafbc6af8
Reviewed-on: https://skia-review.googlesource.com/19266
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/sksl/SkSLSPIRVCodeGenerator.h b/src/sksl/SkSLSPIRVCodeGenerator.h
index a343905..9944428 100644
--- a/src/sksl/SkSLSPIRVCodeGenerator.h
+++ b/src/sksl/SkSLSPIRVCodeGenerator.h
@@ -111,6 +111,8 @@
     SpvId getPointerType(const Type& type, const MemoryLayout& layout,
                          SpvStorageClass_ storageClass);
 
+    void writePrecisionModifier(const Modifiers& modifiers, SpvId id);
+
     std::vector<SpvId> getAccessChain(const Expression& expr, OutputStream& out);
 
     void writeLayout(const Layout& layout, SpvId target);