initial checkin of SkSL compiler

src/sksl/ir/SkSLBlock.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_BLOCK
+#define SKSL_BLOCK
+
+#include "SkSLStatement.h"
+
+namespace SkSL {
+
+/**
+ * A block of multiple statements functioning as a single statement.
+ */
+struct Block : public Statement {
+    Block(Position position, std::vector<std::unique_ptr<Statement>> statements)
+    : INHERITED(position, kBlock_Kind)
+    , fStatements(std::move(statements)) {}
+
+    std::string description() const override {
+        std::string result = "{";
+        for (size_t i = 0; i < fStatements.size(); i++) {
+            result += "\n";
+            result += fStatements[i]->description();
+        }
+        result += "\n}\n";
+        return result;        
+    }
+
+    const std::vector<std::unique_ptr<Statement>> fStatements;
+
+    typedef Statement INHERITED;
+};
+
+} // namespace
+
+#endif