Don't dynamically scope GN templates.

tools/gn/template.cc

+// 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.
+
+#include "tools/gn/template.h"
+
+#include "tools/gn/err.h"
+#include "tools/gn/functions.h"
+#include "tools/gn/parse_tree.h"
+#include "tools/gn/scope.h"
+#include "tools/gn/value.h"
+
+Template::Template(const Scope* scope, const FunctionCallNode* def)
+    : closure_(scope->MakeClosure()),
+      definition_(def) {
+}
+
+Template::Template(scoped_ptr<Scope> scope, const FunctionCallNode* def)
+    : closure_(scope.Pass()),
+      definition_(def) {
+}
+
+Template::~Template() {
+}
+
+scoped_ptr<Template> Template::Clone() const {
+  // We can make a new closure from our closure to copy it.
+  return scoped_ptr<Template>(
+      new Template(closure_->MakeClosure(), definition_));
+}
+
+Value Template::Invoke(Scope* scope,
+                       const FunctionCallNode* invocation,
+                       const std::vector<Value>& args,
+                       BlockNode* block,
+                       Err* err) const {
+  // Don't allow templates to be executed from imported files. Imports are for
+  // simple values only.
+  if (!EnsureNotProcessingImport(invocation, scope, err))
+    return Value();
+
+  // First run the invocation's block.
+  Scope invocation_scope(scope);
+  if (!FillTargetBlockScope(scope, invocation,
+                            invocation->function().value().as_string(),
+                            block, args, &invocation_scope, err))
+    return Value();
+  block->ExecuteBlockInScope(&invocation_scope, err);
+  if (err->has_error())
+    return Value();
+
+  // Set up the scope to run the template. This should be dependent on the
+  // closure, but have the "invoker" and "target_name" values injected, and the
+  // current dir matching the invoker.
+  Scope template_scope(closure_.get());
+  template_scope.SetValue("invoker", Value(NULL, &invocation_scope),
+                          invocation);
+  template_scope.set_source_dir(scope->GetSourceDir());
+
+  const base::StringPiece target_name("target_name");
+  template_scope.SetValue(target_name,
+                          Value(invocation, args[0].string_value()),
+                          invocation);
+
+  // Run the template code. Don't check for unused variables since the
+  // template could be executed in many different ways and it could be that
+  // not all executions use all values in the closure.
+  return definition_->block()->ExecuteBlockInScope(&template_scope, err);
+}
+
+LocationRange Template::GetDefinitionRange() const {
+  return definition_->GetRange();
+}