OOPIF: Support session restore by combining/splitting frame states.

content/renderer/history_serialization.h

 // Copyright 2014 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 CONTENT_RENDERER_HISTORY_SERIALIZATION_H_
 #define CONTENT_RENDERER_HISTORY_SERIALIZATION_H_
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 
 namespace blink {
 class WebHistoryItem;
 }
 
 namespace content {
 class HistoryEntry;
 class PageState;
+struct ExplodedFrameState;
 
 CONTENT_EXPORT PageState HistoryEntryToPageState(HistoryEntry* entry);
 CONTENT_EXPORT PageState SingleHistoryItemToPageState(
     const blink::WebHistoryItem& item);
 CONTENT_EXPORT scoped_ptr<HistoryEntry> PageStateToHistoryEntry(
     const PageState& state);
 
+CONTENT_EXPORT ExplodedFrameState
+HistoryItemToFrameState(const blink::WebHistoryItem& item);
+CONTENT_EXPORT blink::WebHistoryItem FrameStateToHistoryItem(
+    const ExplodedFrameState& state);
+
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_HISTORY_SERIALIZATION_H_