Allow embedder to use custom cryptography in Autofill table.

components/autofill/core/browser/webdata/autofill_table_encryptor_factory.h

Index: components/autofill/core/browser/webdata/autofill_table_encryptor_factory.h
diff --git a/components/autofill/core/browser/webdata/autofill_table_encryptor_factory.h b/components/autofill/core/browser/webdata/autofill_table_encryptor_factory.h
new file mode 100644
index 0000000000000000000000000000000000000000..aa0d52de6016a04c3579898d848885bcd0ba16ed
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+++ b/components/autofill/core/browser/webdata/autofill_table_encryptor_factory.h
@@ -0,0 +1,53 @@
+// Copyright 2017 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_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_TABLE_ENCRYPTOR_FACTORY_H_
+#define COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_TABLE_ENCRYPTOR_FACTORY_H_
+
+#include <memory>
+
+#include "base/sequence_checker.h"
+
+namespace base {
+template <typename T>
+struct DefaultSingletonTraits;
+}  // namespace base
+
+namespace autofill {
+
+class AutofillTableEncryptor;
+
+// Factory for creating Autofill table encryptor.
+// If |delegate_| is set, then |delegate_| is used to create encryptor,
+// else default encrytor (SystemEncryptor) is returned.
+class AutofillTableEncryptorFactory {
+ public:
+  // Embedders are recommended to use this delegate to inject
+  // their encryptor into Autofill table.
+  class Delegate {
+   public:
+    virtual ~Delegate() = default;
+
+    virtual std::unique_ptr<AutofillTableEncryptor> Create() = 0;
+  };
+
+  static AutofillTableEncryptorFactory* GetInstance();
+
+  std::unique_ptr<AutofillTableEncryptor> Create();
+
+  void SetDelegate(std::unique_ptr<Delegate> delegate);
+
+ private:
+  AutofillTableEncryptorFactory();
+  ~AutofillTableEncryptorFactory();
+
+  std::unique_ptr<Delegate> delegate_;
+  base::SequenceChecker sequence_checker_;
+
+  friend struct base::DefaultSingletonTraits<AutofillTableEncryptorFactory>;
+  DISALLOW_COPY_AND_ASSIGN(AutofillTableEncryptorFactory);
+};
+
+}  // namespace autofill
+
+#endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_WEBDATA_AUTOFILL_TABLE_ENCRYPTOR_FACTORY_H_