initial checkin of SkSL compiler

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1984363002
CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Ubuntu-GCC-x86_64-Release-CMake-Trybot,Build-Mac-Clang-x86_64-Release-CMake-Trybot

Review-Url: https://codereview.chromium.org/1984363002
diff --git a/src/sksl/SkSLCodeGenerator.h b/src/sksl/SkSLCodeGenerator.h
new file mode 100644
index 0000000..cd50cc8
--- /dev/null
+++ b/src/sksl/SkSLCodeGenerator.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+ 
+#ifndef SKSL_CODEGENERATOR
+#define SKSL_CODEGENERATOR
+
+#include "ir/SkSLProgram.h"
+#include <vector>
+#include <iostream>
+
+namespace SkSL {
+
+/**
+ * Abstract superclass of all code generators, which take a Program as input and produce code as
+ * output.
+ */
+class CodeGenerator {
+public:
+	virtual ~CodeGenerator() {}
+	
+    virtual void generateCode(Program& program, std::ostream& out) = 0;
+};
+
+} // namespace
+
+#endif