Moved NavigationManagerImpl serialization out of CRWSessionController.

ios/web/navigation/navigation_manager_serialization_builder.h

Index: ios/web/navigation/navigation_manager_serialization_builder.h
diff --git a/ios/web/navigation/navigation_manager_serialization_builder.h b/ios/web/navigation/navigation_manager_serialization_builder.h
new file mode 100644
index 0000000000000000000000000000000000000000..7c536808235d07cabf4ed726de32be88c25553cf
--- /dev/null
+++ b/ios/web/navigation/navigation_manager_serialization_builder.h
@@ -0,0 +1,30 @@
+// Copyright 2015 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 IOS_WEB_NAVIGATION_SERIALIZED_NAVIGATION_MANAGER_BUILDER_H_
+#define IOS_WEB_NAVIGATION_SERIALIZED_NAVIGATION_MANAGER_BUILDER_H_
+
+#include <memory>
+
+@class CRWNavigationManagerSerialization;
+
+namespace web {
+
+class NavigationManagerImpl;
+
+// Class that can serialize and deserialize NavigationManagers.
+class NavigationManagerSerializationBuilder {
+ public:
+  // Creates a serialized NavigationManager from |navigation_manager|.
+  CRWNavigationManagerSerialization* BuildSerialization(
+      NavigationManagerImpl* navigation_manager) const;
+  // Creates a NavigationManager from |navigation_manager_serialization|.
+  std::unique_ptr<NavigationManagerImpl> BuildNavigationManagerImpl(
+      CRWNavigationManagerSerialization* navigation_manager_serialization)
+      const;
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_NAVIGATION_SERIALIZED_NAVIGATION_MANAGER_BUILDER_H_