Re-re-land sksl fragment processor support

This reverts commit 5ce397205528f82084fc650c2ce27d246c01da33.

Bug: skia:
Change-Id: I88260c90004610a1cf8ad1a87c2b4b222525bbb6
Reviewed-on: https://skia-review.googlesource.com/21108
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/sksl/ast/SkSLASTSection.h b/src/sksl/ast/SkSLASTSection.h
new file mode 100644
index 0000000..d0887e2
--- /dev/null
+++ b/src/sksl/ast/SkSLASTSection.h
@@ -0,0 +1,43 @@
+/*
+ * 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_ASTSECTION
+#define SKSL_ASTSECTION
+
+#include "SkSLASTDeclaration.h"
+
+namespace SkSL {
+
+/**
+ * A section declaration (e.g. @body { body code here })..
+ */
+struct ASTSection : public ASTDeclaration {
+    ASTSection(Position position, String name, String arg, String text)
+    : INHERITED(position, kSection_Kind)
+    , fName(std::move(name))
+    , fArgument(std::move(arg))
+    , fText(std::move(text)) {}
+
+    String description() const override {
+        String result = "@" + fName;
+        if (fArgument.size()) {
+            result += "(" + fArgument + ")";
+        }
+        result += " { " + fText + " }";
+        return result;
+    }
+
+    const String fName;
+    const String fArgument;
+    const String fText;
+
+    typedef ASTDeclaration INHERITED;
+};
+
+} // namespace
+
+#endif