SPIR-V geometry shader support

Bug: skia:
Change-Id: Ie6808eae3fb534257f79b63307c3d65391b60965
Reviewed-on: https://skia-review.googlesource.com/23141
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Chris Dalton <csmartdalton@google.com>
diff --git a/src/sksl/SkSLSPIRVCodeGenerator.h b/src/sksl/SkSLSPIRVCodeGenerator.h
index 5db4bb4..a532c9a 100644
--- a/src/sksl/SkSLSPIRVCodeGenerator.h
+++ b/src/sksl/SkSLSPIRVCodeGenerator.h
@@ -277,6 +277,8 @@
                           int32_t word5, int32_t word6, int32_t word7, int32_t word8,
                           OutputStream& out);
 
+    void writeGeometryShaderExecutionMode(SpvId entryPoint, OutputStream& out);
+
     const Context& fContext;
     const MemoryLayout fDefaultLayout;