Factor DocumentSubresourceFilter out of SubresourceFilterAgent.

components/subresource_filter/core/common/test_ruleset_creator.cc

Index: components/subresource_filter/core/common/test_ruleset_creator.cc
diff --git a/components/subresource_filter/core/common/test_ruleset_creator.cc b/components/subresource_filter/core/common/test_ruleset_creator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b2255fd3e38bc7f90e6a2d84f694c78953bbfb72
--- /dev/null
+++ b/components/subresource_filter/core/common/test_ruleset_creator.cc
@@ -0,0 +1,35 @@
+// 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 "components/subresource_filter/core/common/test_ruleset_creator.h"
+
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace subresource_filter {
+namespace testing {
+
+TestRulesetCreator::TestRulesetCreator() = default;
+TestRulesetCreator::~TestRulesetCreator() = default;
+
+void TestRulesetCreator::CreateRulesetToDisallowURLsWithPathSuffix(
+    base::StringPiece suffix,
+    base::File* ruleset_file) {
+  DCHECK(ruleset_file);
+  ASSERT_TRUE(scoped_temp_dir_.IsValid() ||
+              scoped_temp_dir_.CreateUniqueTempDir());
+  base::FilePath unique_temp_path = scoped_temp_dir_.path().AppendASCII(
+      base::IntToString(next_ruleset_version_++));
+  int ruleset_size = base::checked_cast<int>(suffix.size());
+  ASSERT_EQ(ruleset_size,
+            base::WriteFile(unique_temp_path, suffix.data(), ruleset_size));
+  ruleset_file->Initialize(unique_temp_path, base::File::FLAG_OPEN |
+                                                 base::File::FLAG_READ |
+                                                 base::File::FLAG_SHARE_DELETE);
+}
+
+}  // namespace testing
+}  // namespace subresource_filter