Introduce content::PageState (again).

components/sessions/serialized_navigation_entry.h

Index: components/sessions/serialized_navigation_entry.h
diff --git a/components/sessions/serialized_navigation_entry.h b/components/sessions/serialized_navigation_entry.h
index bc727005e4982c7bb9cfaab68ec9e4ac7354c483..f76642babde1e1ef420aa53a70d369c4f265d129 100644
--- a/components/sessions/serialized_navigation_entry.h
+++ b/components/sessions/serialized_navigation_entry.h
@@ -14,6 +14,7 @@
 #include "base/string16.h"
 #include "base/time.h"
 #include "components/sessions/sessions_export.h"
+#include "content/public/common/page_state.h"
 #include "content/public/common/page_transition_types.h"
 #include "content/public/common/referrer.h"
 #include "googleurl/src/gurl.h"
@@ -96,7 +97,7 @@ class SESSIONS_EXPORT SerializedNavigationEntry {
   int unique_id() const { return unique_id_; }
   const GURL& virtual_url() const { return virtual_url_; }
   const string16& title() const { return title_; }
-  const std::string& content_state() const { return content_state_; }
+  const content::PageState& page_state() const { return page_state_; }
   const string16& search_terms() const { return search_terms_; }
   const GURL& favicon_url() const { return favicon_url_; }
   const content::Referrer& referrer() const { return referrer_; }
@@ -139,7 +140,7 @@ class SESSIONS_EXPORT SerializedNavigationEntry {
   content::Referrer referrer_;
   GURL virtual_url_;
   string16 title_;
-  std::string content_state_;
+  content::PageState page_state_;
   content::PageTransition transition_type_;
   bool has_post_data_;
   int64 post_id_;