Don't dynamically scope GN templates.

tools/gn/template.h

+// Copyright 2014 The Chromium 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 TOOLS_GN_TEMPLATE_H_
+#define TOOLS_GN_TEMPLATE_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+
+class BlockNode;
+class Err;
+class FunctionCallNode;
+class LocationRange;
+class Scope;
+class Value;
+
+class Template {
+ public:
+  // Makes a new closure based on the given scope.
+  Template(const Scope* scope, const FunctionCallNode* def);
+
+  // Takes ownership of a previously-constructed closure.
+  Template(scoped_ptr<Scope> closure, const FunctionCallNode* def);
+
+  ~Template();
+
+  // Makes a copy of this template.
+  scoped_ptr<Template> Clone() const;
+
+  // Invoke the template. The values correspond to the state of the code
+  // invoking the template.
+  Value Invoke(Scope* scope,
+               const FunctionCallNode* invocation,
+               const std::vector<Value>& args,
+               BlockNode* block,
+               Err* err) const;
+
+  // Returns the location range where this template was defined.
+  LocationRange GetDefinitionRange() const;
+
+ private:
+  Template();
+
+  scoped_ptr<Scope> closure_;
+  const FunctionCallNode* definition_;
+
+  DISALLOW_COPY_AND_ASSIGN(Template);
+};
+
+#endif  // TOOLS_GN_TEMPLATE_H_