Factor DocumentSubresourceFilter out of SubresourceFilterAgent.

components/subresource_filter/core/common/test_ruleset_creator.h

Index: components/subresource_filter/core/common/test_ruleset_creator.h
diff --git a/components/subresource_filter/core/common/test_ruleset_creator.h b/components/subresource_filter/core/common/test_ruleset_creator.h
new file mode 100644
index 0000000000000000000000000000000000000000..3601b98163d0f31c207921370fb3483558c52d67
--- /dev/null
+++ b/components/subresource_filter/core/common/test_ruleset_creator.h
@@ -0,0 +1,45 @@
+// 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.
+
+#ifndef COMPONENTS_SUBRESOURCE_FILTER_CORE_COMMON_TEST_RULESET_CREATOR_H_
+#define COMPONENTS_SUBRESOURCE_FILTER_CORE_COMMON_TEST_RULESET_CREATOR_H_
+
+#include "base/files/file.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/macros.h"
+#include "base/strings/string_piece.h"
+
+namespace subresource_filter {
+namespace testing {
+
+// Helper class to create subresource filtering rulesets for testing.
+class TestRulesetCreator {
+ public:
+  TestRulesetCreator();
+  ~TestRulesetCreator();
+
+  // Creates a testing ruleset to disallow subresource loads from URL paths
+  // having the given |suffix|, and returns a read-only file handle to it in
+  // |ruleset_file|.
+  //
+  // The underlying temporary file will be deleted when the TestRulesetCreator
+  // instance goes out of scope, but the |ruleset_file| handle may outlive and
+  // can still be used even after the destruction.
+  //
+  // Enclose the call to this method in ASSERT_NO_FATAL_FAILURE to detect
+  // errors.
+  void CreateRulesetToDisallowURLsWithPathSuffix(base::StringPiece suffix,
+                                                 base::File* ruleset_file);
+
+ private:
+  base::ScopedTempDir scoped_temp_dir_;
+  int next_ruleset_version_ = 1;
+
+  DISALLOW_COPY_AND_ASSIGN(TestRulesetCreator);
+};
+
+}  // namespace testing
+}  // namespace subresource_filter
+
+#endif  // COMPONENTS_SUBRESOURCE_FILTER_CORE_COMMON_TEST_RULESET_CREATOR_H_