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

content/renderer/history_serialization.h

Index: content/renderer/history_serialization.h
diff --git a/content/renderer/history_serialization.h b/content/renderer/history_serialization.h
index e9752af048e27d525c1d017153a79aca38f1f129..0bf4b81bcad3af46ef839193ede7cf0745ac20ab 100644
--- a/content/renderer/history_serialization.h
+++ b/content/renderer/history_serialization.h
@@ -17,6 +17,7 @@ class WebHistoryItem;
 namespace content {
 class HistoryEntry;
 class PageState;
+struct ExplodedFrameState;
 
 CONTENT_EXPORT PageState HistoryEntryToPageState(HistoryEntry* entry);
 CONTENT_EXPORT PageState SingleHistoryItemToPageState(
@@ -24,6 +25,11 @@ CONTENT_EXPORT PageState SingleHistoryItemToPageState(
 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_