Split parsing of functions and top-level code into two separate methods

src/parsing/parsing.h

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_PARSING_PARSING_H_
+#define V8_PARSING_PARSING_H_
+
+namespace v8 {
+namespace internal {
+
+class ParseInfo;
+
+namespace parsing {
+
+// Parses the top-level source code represented by the parse info and sets its
+// function literal.  Returns false (and deallocates any allocated AST
+// nodes) if parsing failed.
+bool ParseProgram(ParseInfo* info);
+
+// Like ParseProgram but for an individual function.
+bool ParseFunction(ParseInfo* info);
+
+}  // namespace parsing
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_PARSING_PARSING_H_