Add forward_variables_from() and target() to GN

tools/gn/test_with_scope.cc

Index: tools/gn/test_with_scope.cc
diff --git a/tools/gn/test_with_scope.cc b/tools/gn/test_with_scope.cc
index d37b72246247151f4de7715dc4a15cdd0851733d..20551f19475d278c5e68e60a08dba209b772c4e1 100644
--- a/tools/gn/test_with_scope.cc
+++ b/tools/gn/test_with_scope.cc
@@ -12,7 +12,8 @@ TestWithScope::TestWithScope()
     : build_settings_(),
       settings_(&build_settings_, std::string()),
       toolchain_(&settings_, Label(SourceDir("//toolchain/"), "default")),
-      scope_(&settings_) {
+      scope_(&settings_),
+      scope_progammatic_provider_(&scope_, true) {
   build_settings_.SetBuildDir(SourceDir("//out/Debug/"));
   build_settings_.set_print_callback(
       base::Bind(&TestWithScope::AppendPrintOutput, base::Unretained(this)));