initial checkin of SkSL compiler

src/sksl/ast/SkSLASTDeclaration.h

Index: src/sksl/ast/SkSLASTDeclaration.h
diff --git a/src/sksl/ast/SkSLASTDeclaration.h b/src/sksl/ast/SkSLASTDeclaration.h
new file mode 100644
index 0000000000000000000000000000000000000000..8b55ecf832ecf24d3c70f4c8191ef80f85ee75e6
--- /dev/null
+++ b/src/sksl/ast/SkSLASTDeclaration.h
@@ -0,0 +1,37 @@
+/*
+ * 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_ASTDECLARATION
+#define SKSL_ASTDECLARATION
+
+#include "SkSLASTPositionNode.h"
+
+namespace SkSL {
+
+/**
+ * Abstract supertype of declarations such as variables and functions. 
+ */
+struct ASTDeclaration : public ASTPositionNode {
+    enum Kind {
+        kVar_Kind,
+        kFunction_Kind,
+        kInterfaceBlock_Kind,
+        kExtension_Kind
+    };
+
+    ASTDeclaration(Position position, Kind kind)
+    : INHERITED(position)
+    , fKind(kind) {}
+
+    Kind fKind;
+
+    typedef ASTPositionNode INHERITED;
+};
+
+} // namespace
+
+#endif