initial checkin of SkSL compiler

src/sksl/ir/SkSLProgramElement.h

+/*
+ * 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_PROGRAMELEMENT
+#define SKSL_PROGRAMELEMENT
+
+#include "SkSLIRNode.h"
+
+namespace SkSL {
+
+/**
+ * Represents a top-level element (e.g. function or global variable) in a program.
+ */
+struct ProgramElement : public IRNode {
+    enum Kind {
+        kVar_Kind,
+        kFunction_Kind,
+        kInterfaceBlock_Kind,
+        kExtension_Kind
+    };
+
+    ProgramElement(Position position, Kind kind)
+    : INHERITED(position)
+    , fKind(kind) {}
+
+    Kind fKind;
+
+    typedef IRNode INHERITED;
+};
+
+} // namespace
+
+#endif