🚙 GN: Add write_runtime_deps variable

tools/gn/group_target_generator_unittest.cc

+// Copyright 2016 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 "testing/gtest/include/gtest/gtest.h"
+#include "tools/gn/group_target_generator.h"
+#include "tools/gn/scheduler.h"
+#include "tools/gn/test_with_scope.h"
+
+namespace {
+
+// Returns true on success, false if write_file signaled an error.
+bool ParseWriteRuntimeDeps(Scope* scope, const std::string& value) {
+  TestParseInput input(
+      "group(\"foo\") { write_runtime_deps = " + value + "}");
+  if (input.has_error())
+    return false;
+
+  Err err;
+  input.parsed()->Execute(scope, &err);
+  return !err.has_error();
+}
+
+}  // namespace
+
+
+// Tests that actions can't have output substitutions.
+TEST(GroupTargetGenerator, WriteRuntimeDeps) {
+  Scheduler scheduler;
+  TestWithScope setup;
+  Scope::ItemVector items_;
+  setup.scope()->set_item_collector(&items_);
+
+  // Should refuse to write files outside of the output dir.
+  EXPECT_FALSE(ParseWriteRuntimeDeps(setup.scope(), "\"//foo.txt\""));
+  EXPECT_EQ(0U, scheduler.GetWriteRuntimeDepsTargets().size());
+
+  // Should fail for garbage inputs.
+  EXPECT_FALSE(ParseWriteRuntimeDeps(setup.scope(), "0"));
+  EXPECT_EQ(0U, scheduler.GetWriteRuntimeDepsTargets().size());
+
+  // Should be able to write inside the out dir.
+  EXPECT_TRUE(ParseWriteRuntimeDeps(setup.scope(), "\"//out/Debug/foo.txt\""));
+  EXPECT_EQ(1U, scheduler.GetWriteRuntimeDepsTargets().size());
+}
+