diff -r 000000000000 -r 6474c204b198 docshell/shistory/src/nsSHEntryShared.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docshell/shistory/src/nsSHEntryShared.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,92 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsSHEntryShared_h__
+#define nsSHEntryShared_h__
+
+#include "nsCOMPtr.h"
+#include "nsAutoPtr.h"
+#include "nsCOMArray.h"
+#include "nsIBFCacheEntry.h"
+#include "nsIMutationObserver.h"
+#include "nsExpirationTracker.h"
+#include "nsRect.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+
+class nsSHEntry;
+class nsISHEntry;
+class nsIDocument;
+class nsIContentViewer;
+class nsIDocShellTreeItem;
+class nsILayoutHistoryState;
+class nsDocShellEditorData;
+class nsISupportsArray;
+
+// A document may have multiple SHEntries, either due to hash navigations or
+// calls to history.pushState.  SHEntries corresponding to the same document
+// share many members; in particular, they share state related to the
+// back/forward cache.
+//
+// nsSHEntryShared is the vehicle for this sharing.
+class nsSHEntryShared MOZ_FINAL : public nsIBFCacheEntry,
+                                  public nsIMutationObserver
+{
+  public:
+    static void Startup();
+    static void Shutdown();
+
+    nsSHEntryShared();
+    ~nsSHEntryShared();
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIMUTATIONOBSERVER
+    NS_DECL_NSIBFCACHEENTRY
+
+  private:
+    friend class nsSHEntry;
+
+    friend class HistoryTracker;
+    friend class nsExpirationTracker<nsSHEntryShared, 3>;
+    nsExpirationState *GetExpirationState() { return &mExpirationState; }
+
+    static already_AddRefed<nsSHEntryShared> Duplicate(nsSHEntryShared *aEntry);
+
+    void RemoveFromExpirationTracker();
+    void Expire();
+    nsresult SyncPresentationState();
+    void DropPresentationState();
+
+    nsresult SetContentViewer(nsIContentViewer *aViewer);
+
+    // See nsISHEntry.idl for an explanation of these members.
+
+    // These members are copied by nsSHEntryShared::Duplicate().  If you add a
+    // member here, be sure to update the Duplicate() implementation.
+    uint64_t                        mDocShellID;
+    nsCOMArray<nsIDocShellTreeItem> mChildShells;
+    nsCOMPtr<nsISupports>           mOwner;
+    nsCString                       mContentType;
+    bool                            mIsFrameNavigation;
+    bool                            mSaveLayoutState;
+    bool                            mSticky;
+    bool                            mDynamicallyCreated;
+    nsCOMPtr<nsISupports>           mCacheKey;
+    uint32_t                        mLastTouched;
+
+    // These members aren't copied by nsSHEntryShared::Duplicate() because
+    // they're specific to a particular content viewer.
+    uint64_t                        mID;
+    nsCOMPtr<nsIContentViewer>      mContentViewer;
+    nsCOMPtr<nsIDocument>           mDocument;
+    nsCOMPtr<nsILayoutHistoryState> mLayoutHistoryState;
+    bool                            mExpired;
+    nsCOMPtr<nsISupports>           mWindowState;
+    nsIntRect                       mViewerBounds;
+    nsCOMPtr<nsISupportsArray>      mRefreshURIList;
+    nsExpirationState               mExpirationState;
+    nsAutoPtr<nsDocShellEditorData> mEditorData;
+};
+
+#endif