initial checkin of SkSL compiler

src/sksl/ast/SkSLASTPositionNode.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_ASTPOSITIONNODE
+#define SKSL_ASTPOSITIONNODE
+
+#include "SkSLASTNode.h"
+#include "../SkSLPosition.h"
+
+namespace SkSL {
+
+/**
+ * An AST node with an associated position in the source.
+ */
+struct ASTPositionNode : public ASTNode {
+    ASTPositionNode(Position position)
+    : fPosition(position) {}
+
+    const Position fPosition;
+};
+
+} // namespace
+
+#endif