diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index fe5b21c538a..390cb1959fa 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -2400,7 +2400,7 @@ nsDocShell::GetSessionStorageForPrincipal(nsIPrincipal* aPrincipal,
         if (!pistorage)
             return NS_ERROR_FAILURE;
 
-        rv = pistorage->InitAsSessionStorage(aPrincipal, aDocumentURI);
+        rv = pistorage->InitAsSessionStorage(aPrincipal, aDocumentURI, mInPrivateBrowsing);
         if (NS_FAILED(rv))
             return rv;
 
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 2b613b06dfa..25f4cd500cd 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -104,6 +104,7 @@
 #include "nsIHttpProtocolHandler.h"
 #include "nsIJSContextStack.h"
 #include "nsIJSRuntimeService.h"
+#include "nsILoadContext.h"
 #include "nsIMarkupDocumentViewer.h"
 #include "nsIPresShell.h"
 #include "nsIPrivateDOMEvent.h"
@@ -2243,6 +2244,19 @@ nsGlobalWindow::SetDocShell(nsIDocShell* aDocShell)
     bool docShellActive;
     mDocShell->GetIsActive(&docShellActive);
     mIsBackground = !docShellActive;
+
+    if (mLocalStorage) {
+      nsCOMPtr<nsIPrivacyTransitionObserver> obs = do_GetInterface(mLocalStorage);
+      if (obs) {
+        mDocShell->AddWeakPrivacyTransitionObserver(obs);
+      }
+    }
+    if (mSessionStorage) {
+      nsCOMPtr<nsIPrivacyTransitionObserver> obs = do_GetInterface(mSessionStorage);
+      if (obs) {
+        mDocShell->AddWeakPrivacyTransitionObserver(obs);
+      }
+    }
   }
 }
 
@@ -8084,6 +8098,11 @@ nsGlobalWindow::GetSessionStorage(nsIDOMStorage ** aSessionStorage)
     if (!mSessionStorage) {
       return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
     }
+
+    nsCOMPtr<nsIPrivacyTransitionObserver> obs = do_GetInterface(mSessionStorage);
+    if (obs) {
+      docShell->AddWeakPrivacyTransitionObserver(obs);
+    }
   }
 
 #ifdef PR_LOGGING
@@ -8113,8 +8132,7 @@ nsGlobalWindow::GetLocalStorage(nsIDOMStorage ** aLocalStorage)
 
     nsresult rv;
 
-    bool unused;
-    if (!nsDOMStorage::CanUseStorage(&unused))
+    if (!nsDOMStorage::CanUseStorage())
       return NS_ERROR_DOM_SECURITY_ERR;
 
     nsIPrincipal *principal = GetPrincipal();
@@ -8130,10 +8148,19 @@ nsGlobalWindow::GetLocalStorage(nsIDOMStorage ** aLocalStorage)
       mDocument->GetDocumentURI(documentURI);
     }
 
+    nsIDocShell* docShell = GetDocShell();
+    nsCOMPtr<nsILoadContext> loadContext = do_QueryInterface(docShell);
+
     rv = storageManager->GetLocalStorageForPrincipal(principal,
                                                      documentURI,
+                                                     loadContext && loadContext->UsePrivateBrowsing(),
                                                      getter_AddRefs(mLocalStorage));
     NS_ENSURE_SUCCESS(rv, rv);
+
+    nsCOMPtr<nsIPrivacyTransitionObserver> obs = do_GetInterface(mLocalStorage);
+    if (obs) {
+      docShell->AddWeakPrivacyTransitionObserver(obs);
+    }
   }
 
   NS_ADDREF(*aLocalStorage = mLocalStorage);
diff --git a/dom/indexedDB/CheckPermissionsHelper.cpp b/dom/indexedDB/CheckPermissionsHelper.cpp
index d760db7467c..1d0009c4009 100644
--- a/dom/indexedDB/CheckPermissionsHelper.cpp
+++ b/dom/indexedDB/CheckPermissionsHelper.cpp
@@ -7,6 +7,8 @@
 #include "CheckPermissionsHelper.h"
 
 #include "nsIDOMWindow.h"
+#include "nsILoadContext.h"
+#include "nsIWebNavigation.h"
 #include "nsIObserverService.h"
 #include "nsIPermissionManager.h"
 #include "nsIPrincipal.h"
@@ -56,7 +58,9 @@ GetIndexedDBPermissions(const nsACString& aASCIIOrigin,
     return nsIPermissionManager::ALLOW_ACTION;
   }
 
-  if (nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode()) {
+  nsCOMPtr<nsIWebNavigation> webNav = do_GetInterface(aWindow);
+  nsCOMPtr<nsILoadContext> loadContext = do_QueryInterface(webNav);
+  if (loadContext && loadContext->UsePrivateBrowsing()) {
     // TODO Support private browsing indexedDB?
     return nsIPermissionManager::DENY_ACTION;
   }
diff --git a/dom/interfaces/storage/nsIDOMStorageManager.idl b/dom/interfaces/storage/nsIDOMStorageManager.idl
index 5f8c205ef1f..94b8789f5f0 100644
--- a/dom/interfaces/storage/nsIDOMStorageManager.idl
+++ b/dom/interfaces/storage/nsIDOMStorageManager.idl
@@ -8,7 +8,7 @@
 interface nsIDOMStorage;
 interface nsIPrincipal;
 
-[scriptable, uuid(fd91ec36-7da8-43bb-b8f2-4b57a862a467)]
+[scriptable, uuid(1541da6c-a9fb-4a8f-af9d-4493c981491d)]
 interface nsIDOMStorageManager : nsISupports
 {
   /**
@@ -33,5 +33,6 @@ interface nsIDOMStorageManager : nsISupports
    * for a single origin.
    */
   nsIDOMStorage getLocalStorageForPrincipal(in nsIPrincipal aPrincipal,
-                                            in DOMString aDocumentURI);
+                                            in DOMString aDocumentURI,
+                                            [optional] in bool aPrivate);
 };
diff --git a/dom/interfaces/storage/nsPIDOMStorage.h b/dom/interfaces/storage/nsPIDOMStorage.h
index 9880efc3349..fabb5ccdd73 100644
--- a/dom/interfaces/storage/nsPIDOMStorage.h
+++ b/dom/interfaces/storage/nsPIDOMStorage.h
@@ -29,8 +29,10 @@ public:
     SessionStorage = 2
   } nsDOMStorageType;
 
-  virtual nsresult InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI) = 0;
-  virtual nsresult InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI) = 0;
+  virtual nsresult InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                        bool aPrivate) = 0;
+  virtual nsresult InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                      bool aPrivate) = 0;
 
   virtual already_AddRefed<nsIDOMStorage> Clone() = 0;
   virtual already_AddRefed<nsIDOMStorage> Fork(const nsSubstring &aDocumentURI) = 0;
diff --git a/dom/src/storage/PStorage.ipdl b/dom/src/storage/PStorage.ipdl
index 1145f62d5fb..9fa6b507ce1 100644
--- a/dom/src/storage/PStorage.ipdl
+++ b/dom/src/storage/PStorage.ipdl
@@ -35,8 +35,8 @@ sync protocol PStorage
 parent:
   __delete__();
 
-  Init(bool useDB, bool canUseChromePersist, bool sessionOnly, nsCString domain,
-       nsCString scopeDBKey, nsCString quotaDomainDBKey,
+  Init(bool useDB, bool canUseChromePersist, bool sessionOnly, bool isPrivate,
+       nsCString domain, nsCString scopeDBKey, nsCString quotaDomainDBKey,
        nsCString quotaETLDplus1DomainDBKey, PRUint32 storageType);
   
   sync GetKeys(bool callerSecure)
@@ -60,6 +60,8 @@ parent:
       returns (nsresult rv);
   sync SetSecure(nsString key, bool secure)
       returns (nsresult rv);
+
+  UpdatePrivateState(bool enabled);
 };
 
 }
diff --git a/dom/src/storage/StorageChild.cpp b/dom/src/storage/StorageChild.cpp
index 207c97be6c4..41cc7bdf9cf 100644
--- a/dom/src/storage/StorageChild.cpp
+++ b/dom/src/storage/StorageChild.cpp
@@ -15,7 +15,9 @@ NS_IMPL_CYCLE_COLLECTION_1(StorageChild, mStorage)
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(StorageChild)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(StorageChild)
-  NS_INTERFACE_MAP_ENTRY(nsISupports)
+  NS_INTERFACE_MAP_ENTRY(nsIPrivacyTransitionObserver)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrivacyTransitionObserver)
 NS_INTERFACE_MAP_END
 
 NS_IMETHODIMP_(nsrefcnt) StorageChild::Release(void)
@@ -79,21 +81,21 @@ StorageChild::InitRemote()
   ContentChild* child = ContentChild::GetSingleton();
   AddIPDLReference();
   child->SendPStorageConstructor(this, null_t());
-  SendInit(mUseDB, mCanUseChromePersist, mSessionOnly, mDomain, mScopeDBKey,
+  SendInit(mUseDB, mCanUseChromePersist, mSessionOnly, mInPrivateBrowsing, mDomain, mScopeDBKey,
            mQuotaDomainDBKey, mQuotaETLDplus1DomainDBKey, mStorageType);
 }
 
 void
-StorageChild::InitAsSessionStorage(nsIURI* aDomainURI)
+StorageChild::InitAsSessionStorage(nsIURI* aDomainURI, bool aPrivate)
 {
-  DOMStorageBase::InitAsSessionStorage(aDomainURI);
+  DOMStorageBase::InitAsSessionStorage(aDomainURI, aPrivate);
   InitRemote();
 }
 
 void
-StorageChild::InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist)
+StorageChild::InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist, bool aPrivate)
 {
-  DOMStorageBase::InitAsLocalStorage(aDomainURI, aCanUseChromePersist);
+  DOMStorageBase::InitAsLocalStorage(aDomainURI, aCanUseChromePersist, aPrivate);
   InitRemote();
 }
 
@@ -234,8 +236,16 @@ StorageChild::CloneFrom(bool aCallerSecure, DOMStorageBase* aThat)
   StorageClone clone(nsnull, other, aCallerSecure);
   AddIPDLReference();
   child->SendPStorageConstructor(this, clone);
-  SendInit(mUseDB, mCanUseChromePersist, mSessionOnly, mDomain, mScopeDBKey,
-           mQuotaDomainDBKey, mQuotaETLDplus1DomainDBKey, mStorageType);
+  SendInit(mUseDB, mCanUseChromePersist, mSessionOnly, mInPrivateBrowsing, mDomain,
+           mScopeDBKey, mQuotaDomainDBKey, mQuotaETLDplus1DomainDBKey, mStorageType);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+StorageChild::PrivateModeChanged(bool enabled)
+{
+  mInPrivateBrowsing = enabled;
+  SendUpdatePrivateState(enabled);
   return NS_OK;
 }
 
diff --git a/dom/src/storage/StorageChild.h b/dom/src/storage/StorageChild.h
index 2547e9aa117..db941b705c9 100644
--- a/dom/src/storage/StorageChild.h
+++ b/dom/src/storage/StorageChild.h
@@ -16,16 +16,18 @@ namespace dom {
 
 class StorageChild : public PStorageChild
                    , public DOMStorageBase
+                   , public nsSupportsWeakReference
 {
 public:
-  NS_DECL_CYCLE_COLLECTION_CLASS(StorageChild)
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(StorageChild, nsIPrivacyTransitionObserver)
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_NSIPRIVACYTRANSITIONOBSERVER
   
   StorageChild(nsDOMStorage* aOwner);
   StorageChild(nsDOMStorage* aOwner, StorageChild& aOther);
 
-  virtual void InitAsSessionStorage(nsIURI* aDomainURI);
-  virtual void InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist);
+  virtual void InitAsSessionStorage(nsIURI* aDomainURI, bool aPrivate);
+  virtual void InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist, bool aPrivate);
 
   virtual bool CacheStoragePermissions();
   
diff --git a/dom/src/storage/StorageParent.cpp b/dom/src/storage/StorageParent.cpp
index f5e68ab5131..624a79602ed 100644
--- a/dom/src/storage/StorageParent.cpp
+++ b/dom/src/storage/StorageParent.cpp
@@ -30,18 +30,26 @@ bool
 StorageParent::RecvInit(const bool& aUseDB,
                         const bool& aCanUseChromePersist,
                         const bool& aSessionOnly,
+                        const bool& aPrivate,
                         const nsCString& aDomain,
                         const nsCString& aScopeDBKey,
                         const nsCString& aQuotaDomainDBKey,
                         const nsCString& aQuotaETLDplus1DomainDBKey,
                         const PRUint32& aStorageType)
 {
-  mStorage->InitFromChild(aUseDB, aCanUseChromePersist, aSessionOnly, aDomain,
+  mStorage->InitFromChild(aUseDB, aCanUseChromePersist, aSessionOnly, aPrivate, aDomain,
                           aScopeDBKey, aQuotaDomainDBKey, aQuotaETLDplus1DomainDBKey,
                           aStorageType);
   return true;
 }
 
+bool
+StorageParent::RecvUpdatePrivateState(const bool& aEnabled)
+{
+  mStorage->PrivateModeChanged(aEnabled);
+  return true;
+}
+
 bool
 StorageParent::RecvGetKeys(const bool& aCallerSecure, InfallibleTArray<nsString>* aKeys)
 {
diff --git a/dom/src/storage/StorageParent.h b/dom/src/storage/StorageParent.h
index 6ec8a1c7d5b..1962e85b4e6 100644
--- a/dom/src/storage/StorageParent.h
+++ b/dom/src/storage/StorageParent.h
@@ -45,12 +45,15 @@ private:
   bool RecvInit(const bool& aUseDB,
                 const bool& aCanUseChromePersist,
                 const bool& aSessionOnly,
+                const bool& aPrivate,
                 const nsCString& aDomain,
                 const nsCString& aScopeDBKey,
                 const nsCString& aQuotaDomainDBKey,
                 const nsCString& aQuotaETLDplus1DomainDBKey,
                 const PRUint32& aStorageType);
 
+  bool RecvUpdatePrivateState(const bool& aEnabled);
+
   nsRefPtr<DOMStorageImpl> mStorage;
 };
 
diff --git a/dom/src/storage/nsDOMStorage.cpp b/dom/src/storage/nsDOMStorage.cpp
index 24f338babd7..4652ddc6e5c 100644
--- a/dom/src/storage/nsDOMStorage.cpp
+++ b/dom/src/storage/nsDOMStorage.cpp
@@ -5,8 +5,10 @@
 
 #include "StorageChild.h"
 #include "StorageParent.h"
+#include "mozilla/dom/ContentChild.h"
 #include "nsXULAppAPI.h"
 using mozilla::dom::StorageChild;
+using mozilla::dom::ContentChild;
 
 #include "prnetdb.h"
 #include "nsCOMPtr.h"
@@ -219,7 +221,6 @@ nsSessionStorageEntry::~nsSessionStorageEntry()
 nsDOMStorageManager* nsDOMStorageManager::gStorageManager;
 
 nsDOMStorageManager::nsDOMStorageManager()
-  : mInPrivateBrowsing(false)
 {
 }
 
@@ -252,8 +253,6 @@ nsDOMStorageManager::Initialize()
   NS_ENSURE_SUCCESS(rv, rv);
   rv = os->AddObserver(gStorageManager, "offline-app-removed", true);
   NS_ENSURE_SUCCESS(rv, rv);
-  rv = os->AddObserver(gStorageManager, NS_PRIVATE_BROWSING_SWITCH_TOPIC, true);
-  NS_ENSURE_SUCCESS(rv, rv);
   rv = os->AddObserver(gStorageManager, "profile-after-change", true);
   NS_ENSURE_SUCCESS(rv, rv);
   rv = os->AddObserver(gStorageManager, "perm-changed", true);
@@ -265,6 +264,8 @@ nsDOMStorageManager::Initialize()
   NS_ENSURE_SUCCESS(rv, rv);
   rv = os->AddObserver(gStorageManager, NS_DOMSTORAGE_FLUSH_TIMER_TOPIC, true);
   NS_ENSURE_SUCCESS(rv, rv);
+  rv = os->AddObserver(gStorageManager, "last-pb-context-exited", true);
+  NS_ENSURE_SUCCESS(rv, rv);
 
   return NS_OK;
 }
@@ -361,10 +362,6 @@ nsDOMStorageManager::Observe(nsISupports *aSubject,
                              const PRUnichar *aData)
 {
   if (!strcmp(aTopic, "profile-after-change")) {
-    nsCOMPtr<nsIPrivateBrowsingService> pbs =
-      do_GetService(NS_PRIVATE_BROWSING_SERVICE_CONTRACTID);
-    if (pbs)
-      pbs->GetPrivateBrowsingEnabled(&gStorageManager->mInPrivateBrowsing);
   }
   else if (!strcmp(aTopic, "offline-app-removed")) {
     nsresult rv = DOMStorageImpl::InitDB();
@@ -383,16 +380,6 @@ nsDOMStorageManager::Observe(nsISupports *aSubject,
     rv = GetOfflineDomains(domains);
     NS_ENSURE_SUCCESS(rv, rv);
     return DOMStorageImpl::gStorageDB->RemoveOwners(domains, true, false);
-  } else if (!strcmp(aTopic, NS_PRIVATE_BROWSING_SWITCH_TOPIC)) {
-    mStorages.EnumerateEntries(ClearStorage, nsnull);
-    if (!nsCRT::strcmp(aData, NS_LITERAL_STRING(NS_PRIVATE_BROWSING_ENTER).get()))
-      mInPrivateBrowsing = true;
-    else if (!nsCRT::strcmp(aData, NS_LITERAL_STRING(NS_PRIVATE_BROWSING_LEAVE).get()))
-      mInPrivateBrowsing = false;
-    nsresult rv = DOMStorageImpl::InitDB();
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    return DOMStorageImpl::gStorageDB->DropPrivateBrowsingStorages();
   } else if (!strcmp(aTopic, "perm-changed")) {
     // Check for cookie permission change
     nsCOMPtr<nsIPermission> perm(do_QueryInterface(aSubject));
@@ -471,6 +458,10 @@ nsDOMStorageManager::Observe(nsISupports *aSubject,
       NS_WARN_IF_FALSE(NS_SUCCEEDED(rv),
                        "DOMStorage: temporary table commit failed");
     }
+  } else if (!strcmp(aTopic, "last-pb-context-exited")) {
+    if (DOMStorageImpl::gStorageDB) {
+      return DOMStorageImpl::gStorageDB->DropPrivateBrowsingStorages();
+    }
   }
 
   return NS_OK;
@@ -484,7 +475,7 @@ nsDOMStorageManager::GetUsage(const nsAString& aDomain,
   NS_ENSURE_SUCCESS(rv, rv);
 
   return DOMStorageImpl::gStorageDB->GetUsage(NS_ConvertUTF16toUTF8(aDomain),
-                                              false, aUsage);
+                                              false, aUsage, false);
 }
 
 NS_IMETHODIMP
@@ -502,6 +493,7 @@ nsDOMStorageManager::ClearOfflineApps()
 NS_IMETHODIMP
 nsDOMStorageManager::GetLocalStorageForPrincipal(nsIPrincipal *aPrincipal,
                                                  const nsSubstring &aDocumentURI,
+                                                 bool aPrivate,
                                                  nsIDOMStorage **aResult)
 {
   NS_ENSURE_ARG_POINTER(aPrincipal);
@@ -513,7 +505,7 @@ nsDOMStorageManager::GetLocalStorageForPrincipal(nsIPrincipal *aPrincipal,
   if (!storage)
     return NS_ERROR_OUT_OF_MEMORY;
 
-  rv = storage->InitAsLocalStorage(aPrincipal, aDocumentURI);
+  rv = storage->InitAsLocalStorage(aPrincipal, aDocumentURI, aPrivate);
   if (NS_FAILED(rv))
     return rv;
 
@@ -570,9 +562,19 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMStorage)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMStorageObsolete)
   NS_INTERFACE_MAP_ENTRY(nsIDOMStorageObsolete)
   NS_INTERFACE_MAP_ENTRY(nsPIDOMStorage)
+  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(StorageObsolete)
 NS_INTERFACE_MAP_END
 
+NS_IMETHODIMP
+nsDOMStorage::GetInterface(const nsIID & aIID, void **result)
+{
+  nsresult rv = mStorageImpl->QueryInterface(aIID, result);
+  if (NS_SUCCEEDED(rv))
+    return rv;
+  return QueryInterface(aIID, result);
+}
+
 nsresult
 NS_NewDOMStorage2(nsISupports* aOuter, REFNSIID aIID, void** aResult)
 {
@@ -585,6 +587,7 @@ DOMStorageBase::DOMStorageBase()
   , mUseDB(false)
   , mSessionOnly(true)
   , mCanUseChromePersist(false)
+  , mInPrivateBrowsing(false)
 {
 }
 
@@ -597,11 +600,12 @@ DOMStorageBase::DOMStorageBase(DOMStorageBase& aThat)
   , mQuotaETLDplus1DomainDBKey(aThat.mQuotaETLDplus1DomainDBKey)
   , mQuotaDomainDBKey(aThat.mQuotaDomainDBKey)
   , mCanUseChromePersist(aThat.mCanUseChromePersist)
+  , mInPrivateBrowsing(aThat.mInPrivateBrowsing)
 {
 }
 
 void
-DOMStorageBase::InitAsSessionStorage(nsIURI* aDomainURI)
+DOMStorageBase::InitAsSessionStorage(nsIURI* aDomainURI, bool aPrivate)
 {
   // No need to check for a return value. If this would fail we would not get
   // here as we call GetPrincipalURIAndHost (nsDOMStorage.cpp:88) from
@@ -614,11 +618,13 @@ DOMStorageBase::InitAsSessionStorage(nsIURI* aDomainURI)
   mScopeDBKey.Truncate();
   mQuotaDomainDBKey.Truncate();
   mStorageType = nsPIDOMStorage::SessionStorage;
+  mInPrivateBrowsing = aPrivate;
 }
 
 void
 DOMStorageBase::InitAsLocalStorage(nsIURI* aDomainURI,
-                                   bool aCanUseChromePersist)
+                                   bool aCanUseChromePersist,
+                                   bool aPrivate)
 {
   // No need to check for a return value. If this would fail we would not get
   // here as we call GetPrincipalURIAndHost (nsDOMStorage.cpp:88) from
@@ -642,6 +648,7 @@ DOMStorageBase::InitAsLocalStorage(nsIURI* aDomainURI,
                                                 true, true, mQuotaETLDplus1DomainDBKey);
   mCanUseChromePersist = aCanUseChromePersist;
   mStorageType = nsPIDOMStorage::LocalStorage;
+  mInPrivateBrowsing = aPrivate;
 }
 
 PLDHashOperator
@@ -667,7 +674,9 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMStorageImpl)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMStorageImpl)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMStorageImpl)
-  NS_INTERFACE_MAP_ENTRY(nsISupports)
+  NS_INTERFACE_MAP_ENTRY(nsIPrivacyTransitionObserver)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrivacyTransitionObserver)
 NS_INTERFACE_MAP_END
 
 DOMStorageImpl::DOMStorageImpl(nsDOMStorage* aStorage)
@@ -723,7 +732,8 @@ DOMStorageImpl::InitDB()
 
 void
 DOMStorageImpl::InitFromChild(bool aUseDB, bool aCanUseChromePersist,
-                              bool aSessionOnly, const nsACString& aDomain,
+                              bool aSessionOnly, bool aPrivate,
+                              const nsACString& aDomain,
                               const nsACString& aScopeDBKey,
                               const nsACString& aQuotaDomainDBKey,
                               const nsACString& aQuotaETLDplus1DomainDBKey,
@@ -732,6 +742,7 @@ DOMStorageImpl::InitFromChild(bool aUseDB, bool aCanUseChromePersist,
   mUseDB = aUseDB;
   mCanUseChromePersist = aCanUseChromePersist;
   mSessionOnly = aSessionOnly;
+  mInPrivateBrowsing = aPrivate;
   mDomain = aDomain;
   mScopeDBKey = aScopeDBKey;
   mQuotaDomainDBKey = aQuotaDomainDBKey;
@@ -746,16 +757,17 @@ DOMStorageImpl::SetSessionOnly(bool aSessionOnly)
 }
 
 void
-DOMStorageImpl::InitAsSessionStorage(nsIURI* aDomainURI)
+DOMStorageImpl::InitAsSessionStorage(nsIURI* aDomainURI, bool aPrivate)
 {
-  DOMStorageBase::InitAsSessionStorage(aDomainURI);
+  DOMStorageBase::InitAsSessionStorage(aDomainURI, aPrivate);
 }
 
 void
 DOMStorageImpl::InitAsLocalStorage(nsIURI* aDomainURI,
-                                   bool aCanUseChromePersist)
+                                   bool aCanUseChromePersist,
+                                   bool aPrivate)
 {
-  DOMStorageBase::InitAsLocalStorage(aDomainURI, aCanUseChromePersist);
+  DOMStorageBase::InitAsLocalStorage(aDomainURI, aCanUseChromePersist, aPrivate);
 }
 
 bool
@@ -765,7 +777,7 @@ DOMStorageImpl::CacheStoragePermissions()
   // All the correct checks have been done on the child, so we just need to
   // make sure that our session-only status is correctly updated.
   if (!mOwner)
-    return nsDOMStorage::CanUseStorage(&mSessionOnly);
+    return CanUseStorage();
   
   return mOwner->CacheStoragePermissions();
 }
@@ -1255,6 +1267,16 @@ DOMStorageImpl::Clear(bool aCallerSecure, PRInt32* aOldCount)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+DOMStorageImpl::PrivateModeChanged(bool enabled)
+{
+  mInPrivateBrowsing = enabled;
+  CanUseStorage(); // cause mSessionOnly to update as well
+  mItems.Clear();
+  mItemsCachedVersion = 0;
+  return NS_OK;
+}
+
 nsDOMStorage::nsDOMStorage()
   : mStorageType(nsPIDOMStorage::Unknown)
   , mEventBroadcaster(nsnull)
@@ -1313,7 +1335,8 @@ GetDomainURI(nsIPrincipal *aPrincipal, bool aIncludeDomain, nsIURI **_domain)
 }
 
 nsresult
-nsDOMStorage::InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI)
+nsDOMStorage::InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                   bool aPrivate)
 {
   nsCOMPtr<nsIURI> domainURI;
   nsresult rv = GetDomainURI(aPrincipal, true, getter_AddRefs(domainURI));
@@ -1324,12 +1347,13 @@ nsDOMStorage::InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &
 
   mStorageType = SessionStorage;
 
-  mStorageImpl->InitAsSessionStorage(domainURI);
+  mStorageImpl->InitAsSessionStorage(domainURI, aPrivate);
   return NS_OK;
 }
 
 nsresult
-nsDOMStorage::InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI)
+nsDOMStorage::InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                 bool aPrivate)
 {
   nsCOMPtr<nsIURI> domainURI;
   nsresult rv = GetDomainURI(aPrincipal, false, getter_AddRefs(domainURI));
@@ -1346,18 +1370,25 @@ nsDOMStorage::InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aD
     canUseChromePersist = URICanUseChromePersist(URI);
   }
   
-  mStorageImpl->InitAsLocalStorage(domainURI, canUseChromePersist);
+  mStorageImpl->InitAsLocalStorage(domainURI, canUseChromePersist, aPrivate);
   return NS_OK;
 }
 
+bool
+DOMStorageBase::CanUseStorage()
+{
+  return nsDOMStorage::CanUseStorage(this);
+}
+
 //static
 bool
-nsDOMStorage::CanUseStorage(bool* aSessionOnly)
+nsDOMStorage::CanUseStorage(DOMStorageBase* aStorage /* = NULL */)
 {
-  // check if the calling domain can use storage. Downgrade to session
-  // only if only session storage may be used.
-  NS_ASSERTION(aSessionOnly, "null session flag");
-  *aSessionOnly = false;
+  if (aStorage) {
+    // check if the calling domain can use storage. Downgrade to session
+    // only if only session storage may be used.
+    aStorage->mSessionOnly = false;
+  }
 
   if (!Preferences::GetBool(kStorageEnabled)) {
     return false;
@@ -1398,8 +1429,9 @@ nsDOMStorage::CanUseStorage(bool* aSessionOnly)
   // mode to prevent detection of being in private browsing mode and ensuring
   // that there will be no traces left.
   if (perm == nsICookiePermission::ACCESS_SESSION ||
-      nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode()) {
-    *aSessionOnly = true;
+      (aStorage && aStorage->IsPrivate())) {
+    if (aStorage)
+      aStorage->mSessionOnly = true;
   }
   else if (perm != nsIPermissionManager::ALLOW_ACTION) {
     PRUint32 cookieBehavior = Preferences::GetUint(kCookiesBehavior);
@@ -1411,8 +1443,8 @@ nsDOMStorage::CanUseStorage(bool* aSessionOnly)
         !URICanUseChromePersist(subjectURI))
       return false;
 
-    if (lifetimePolicy == ACCEPT_SESSION)
-      *aSessionOnly = true;
+    if (lifetimePolicy == ACCEPT_SESSION && aStorage)
+      aStorage->mSessionOnly = true;
   }
 
   return true;
@@ -1424,7 +1456,7 @@ nsDOMStorage::CacheStoragePermissions()
   // Bug 488446, disallowing storage use when in session only mode.
   // This is temporary fix before we find complete solution for storage
   // behavior in private browsing mode or session-only cookies mode.
-  if (!CanUseStorage(&mStorageImpl->mSessionOnly))
+  if (!mStorageImpl->CanUseStorage())
     return false;
 
   nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
@@ -1701,9 +1733,19 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsDOMStorage2)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMStorage)
   NS_INTERFACE_MAP_ENTRY(nsIDOMStorage)
   NS_INTERFACE_MAP_ENTRY(nsPIDOMStorage)
+  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(Storage)
 NS_INTERFACE_MAP_END
 
+NS_IMETHODIMP
+nsDOMStorage2::GetInterface(const nsIID & aIID, void **result)
+{
+  nsresult rv = mStorage->GetInterface(aIID, result);
+  if (NS_SUCCEEDED(rv))
+    return rv;
+  return QueryInterface(aIID, result);;
+}
+
 nsDOMStorage2::nsDOMStorage2()
 {
 }
@@ -1715,7 +1757,8 @@ nsDOMStorage2::nsDOMStorage2(nsDOMStorage2& aThat)
 }
 
 nsresult
-nsDOMStorage2::InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI)
+nsDOMStorage2::InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                    bool aPrivate)
 {
   mStorage = new nsDOMStorage();
   if (!mStorage)
@@ -1724,11 +1767,12 @@ nsDOMStorage2::InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring
   mPrincipal = aPrincipal;
   mDocumentURI = aDocumentURI;
 
-  return mStorage->InitAsSessionStorage(aPrincipal, aDocumentURI);
+  return mStorage->InitAsSessionStorage(aPrincipal, aDocumentURI, aPrivate);
 }
 
 nsresult
-nsDOMStorage2::InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI)
+nsDOMStorage2::InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                  bool aPrivate)
 {
   mStorage = new nsDOMStorage();
   if (!mStorage)
@@ -1737,7 +1781,7 @@ nsDOMStorage2::InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &a
   mPrincipal = aPrincipal;
   mDocumentURI = aDocumentURI;
 
-  return mStorage->InitAsLocalStorage(aPrincipal, aDocumentURI);
+  return mStorage->InitAsLocalStorage(aPrincipal, aDocumentURI, aPrivate);
 }
 
 already_AddRefed<nsIDOMStorage>
@@ -1907,7 +1951,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDOMStorageItem)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDOMStorageItem)
   {
-    cb.NoteXPCOMChild((nsISupports*) tmp->mStorage);
+    cb.NoteXPCOMChild(tmp->mStorage);
   }
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
diff --git a/dom/src/storage/nsDOMStorage.h b/dom/src/storage/nsDOMStorage.h
index 0b3bcb79e6b..bdc3529b8f5 100644
--- a/dom/src/storage/nsDOMStorage.h
+++ b/dom/src/storage/nsDOMStorage.h
@@ -12,6 +12,7 @@
 #include "nsIDOMStorage.h"
 #include "nsIDOMStorageItem.h"
 #include "nsIPermissionManager.h"
+#include "nsIPrivacyTransitionObserver.h"
 #include "nsInterfaceHashtable.h"
 #include "nsVoidArray.h"
 #include "nsTArray.h"
@@ -24,6 +25,7 @@
 #include "nsIObserver.h"
 #include "nsITimer.h"
 #include "nsWeakReference.h"
+#include "nsIInterfaceRequestor.h"
 
 #include "nsDOMStorageDBWrapper.h"
 
@@ -87,8 +89,6 @@ public:
 
   nsresult ClearAllStorages();
 
-  bool InPrivateBrowsingMode() { return mInPrivateBrowsing; }
-
   static nsresult Initialize();
   static nsDOMStorageManager* GetInstance();
   static void Shutdown();
@@ -104,17 +104,16 @@ public:
 protected:
 
   nsTHashtable<nsDOMStorageEntry> mStorages;
-  bool mInPrivateBrowsing;
 };
 
-class DOMStorageBase : public nsISupports
+class DOMStorageBase : public nsIPrivacyTransitionObserver
 {
 public:
   DOMStorageBase();
   DOMStorageBase(DOMStorageBase&);
 
-  virtual void InitAsSessionStorage(nsIURI* aDomainURI);
-  virtual void InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist);
+  virtual void InitAsSessionStorage(nsIURI* aDomainURI, bool aPrivate);
+  virtual void InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist, bool aPrivate);
 
   virtual nsTArray<nsString>* GetKeys(bool aCallerSecure) = 0;
   virtual nsresult GetLength(bool aCallerSecure, PRUint32* aLength) = 0;
@@ -126,7 +125,10 @@ public:
   virtual nsresult RemoveValue(bool aCallerSecure, const nsAString& aKey,
                                nsAString& aOldValue) = 0;
   virtual nsresult Clear(bool aCallerSecure, PRInt32* aOldCount) = 0;
-  
+
+  // Call nsDOMStorage::CanUseStorage with |this|
+  bool CanUseStorage();
+
   // If true, the contents of the storage should be stored in the
   // database, otherwise this storage should act like a session
   // storage.
@@ -137,6 +139,10 @@ public:
     return mUseDB;
   }
 
+  bool IsPrivate() {
+    return mInPrivateBrowsing;
+  }
+
   // retrieve the value and secure state corresponding to a key out of storage.
   virtual nsresult
   GetDBValue(const nsAString& aKey,
@@ -198,21 +204,23 @@ protected:
   nsCString mQuotaDomainDBKey;
 
   bool mCanUseChromePersist;
+  bool mInPrivateBrowsing;
 };
 
 class DOMStorageImpl : public DOMStorageBase
-
+                     , public nsSupportsWeakReference
 {
 public:
-  NS_DECL_CYCLE_COLLECTION_CLASS(DOMStorageImpl)
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(DOMStorageImpl, nsIPrivacyTransitionObserver)
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_NSIPRIVACYTRANSITIONOBSERVER
 
   DOMStorageImpl(nsDOMStorage*);
   DOMStorageImpl(nsDOMStorage*, DOMStorageImpl&);
   ~DOMStorageImpl();
 
-  virtual void InitAsSessionStorage(nsIURI* aDomainURI);
-  virtual void InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist);
+  virtual void InitAsSessionStorage(nsIURI* aDomainURI, bool aPrivate);
+  virtual void InitAsLocalStorage(nsIURI* aDomainURI, bool aCanUseChromePersist, bool aPrivate);
 
   bool SessionOnly() {
     return mSessionOnly;
@@ -283,7 +291,7 @@ private:
   // Cross-process storage implementations never have InitAs(Session|Local|Global)Storage
   // called, so the appropriate initialization needs to happen from the child.
   void InitFromChild(bool aUseDB, bool aCanUseChromePersist, bool aSessionOnly,
-                     const nsACString& aDomain,
+                     bool aPrivate, const nsACString& aDomain,
                      const nsACString& aScopeDBKey,
                      const nsACString& aQuotaDomainDBKey,
                      const nsACString& aQuotaETLDplus1DomainDBKey,
@@ -306,7 +314,8 @@ private:
 class nsDOMStorage2;
 
 class nsDOMStorage : public nsIDOMStorageObsolete,
-                     public nsPIDOMStorage
+                     public nsPIDOMStorage,
+                     public nsIInterfaceRequestor
 {
 public:
   nsDOMStorage();
@@ -317,14 +326,17 @@ public:
   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsDOMStorage, nsIDOMStorageObsolete)
 
   NS_DECL_NSIDOMSTORAGEOBSOLETE
+  NS_DECL_NSIINTERFACEREQUESTOR
 
   // Helpers for implementing nsIDOMStorage
   nsresult GetItem(const nsAString& key, nsAString& aData);
   nsresult Clear();
 
   // nsPIDOMStorage
-  virtual nsresult InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI);
-  virtual nsresult InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI);
+  virtual nsresult InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                        bool aPrivate);
+  virtual nsresult InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                      bool aPrivate);
   virtual already_AddRefed<nsIDOMStorage> Clone();
   virtual already_AddRefed<nsIDOMStorage> Fork(const nsSubstring &aDocumentURI);
   virtual bool IsForkOf(nsIDOMStorage* aThat);
@@ -336,7 +348,7 @@ public:
   // Check whether storage may be used by the caller, and whether it
   // is session only.  Returns true if storage may be used.
   static bool
-  CanUseStorage(bool* aSessionOnly);
+  CanUseStorage(DOMStorageBase* aStorage = nsnull);
 
   // Check whether this URI can use chrome persist storage.  This kind of
   // storage can bypass cookies limits, private browsing and uses the offline
@@ -381,7 +393,8 @@ public:
 };
 
 class nsDOMStorage2 : public nsIDOMStorage,
-                      public nsPIDOMStorage
+                      public nsPIDOMStorage,
+                      public nsIInterfaceRequestor
 {
 public:
   // nsISupports
@@ -392,10 +405,13 @@ public:
   nsDOMStorage2();
 
   NS_DECL_NSIDOMSTORAGE
+  NS_DECL_NSIINTERFACEREQUESTOR
 
   // nsPIDOMStorage
-  virtual nsresult InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI);
-  virtual nsresult InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI);
+  virtual nsresult InitAsSessionStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                        bool aPrivate);
+  virtual nsresult InitAsLocalStorage(nsIPrincipal *aPrincipal, const nsSubstring &aDocumentURI,
+                                      bool aPrivate);
   virtual already_AddRefed<nsIDOMStorage> Clone();
   virtual already_AddRefed<nsIDOMStorage> Fork(const nsSubstring &aDocumentURI);
   virtual bool IsForkOf(nsIDOMStorage* aThat);
diff --git a/dom/src/storage/nsDOMStorageDBWrapper.cpp b/dom/src/storage/nsDOMStorageDBWrapper.cpp
index 1fdc5ff9c72..25af0ddd44e 100644
--- a/dom/src/storage/nsDOMStorageDBWrapper.cpp
+++ b/dom/src/storage/nsDOMStorageDBWrapper.cpp
@@ -90,7 +90,7 @@ nsDOMStorageDBWrapper::FlushAndDeleteTemporaryTables(bool force)
   PR_BEGIN_MACRO                                                      \
   if (aStorage->CanUseChromePersist())                                \
     _return mChromePersistentDB._code;                                \
-  if (nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode())  \
+  if (aStorage->IsPrivate())                                          \
     _return mPrivateBrowsingDB._code;                                 \
   if (aStorage->SessionOnly())                                        \
     _return mSessionOnlyDB._code;                                     \
@@ -188,9 +188,6 @@ nsDOMStorageDBWrapper::RemoveOwner(const nsACString& aOwner,
   rv = mPrivateBrowsingDB.RemoveOwner(aOwner, aIncludeSubDomains);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode())
-    return NS_OK;
-
   rv = mSessionOnlyDB.RemoveOwner(aOwner, aIncludeSubDomains);
   NS_ENSURE_SUCCESS(rv, rv);
 
@@ -210,9 +207,6 @@ nsDOMStorageDBWrapper::RemoveOwners(const nsTArray<nsString> &aOwners,
   rv = mPrivateBrowsingDB.RemoveOwners(aOwners, aIncludeSubDomains, aMatch);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode())
-    return NS_OK;
-
   rv = mSessionOnlyDB.RemoveOwners(aOwners, aIncludeSubDomains, aMatch);
   NS_ENSURE_SUCCESS(rv, rv);
 
@@ -222,26 +216,6 @@ nsDOMStorageDBWrapper::RemoveOwners(const nsTArray<nsString> &aOwners,
   return rv;
 }
 
-nsresult
-nsDOMStorageDBWrapper::RemoveAll()
-{
-  nsresult rv;
-
-  rv = mPrivateBrowsingDB.RemoveAll();
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  if (nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode())
-    return NS_OK;
-
-  rv = mSessionOnlyDB.RemoveAll();
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  rv = mPersistentDB.RemoveAll();
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  return rv;
-}
-
 nsresult
 nsDOMStorageDBWrapper::GetUsage(DOMStorageImpl* aStorage,
                                 bool aExcludeOfflineFromUsage, PRInt32 *aUsage)
@@ -251,9 +225,9 @@ nsDOMStorageDBWrapper::GetUsage(DOMStorageImpl* aStorage,
 
 nsresult
 nsDOMStorageDBWrapper::GetUsage(const nsACString& aDomain,
-                                bool aIncludeSubDomains, PRInt32 *aUsage)
+                                bool aIncludeSubDomains, PRInt32 *aUsage, bool aPrivate)
 {
-  if (nsDOMStorageManager::gStorageManager->InPrivateBrowsingMode())
+  if (aPrivate)
     return mPrivateBrowsingDB.GetUsage(aDomain, aIncludeSubDomains, aUsage);
 
 #if 0
diff --git a/dom/src/storage/nsDOMStorageDBWrapper.h b/dom/src/storage/nsDOMStorageDBWrapper.h
index 34377fdd50f..fdfcb6412ed 100644
--- a/dom/src/storage/nsDOMStorageDBWrapper.h
+++ b/dom/src/storage/nsDOMStorageDBWrapper.h
@@ -144,12 +144,6 @@ public:
   RemoveOwners(const nsTArray<nsString>& aOwners,
                bool aIncludeSubDomains, bool aMatch);
 
-  /**
-   * Removes all keys from storage. Used when clearing storage.
-   */
-  nsresult
-  RemoveAll();
-
   /**
     * Returns usage for a storage using its GetQuotaDomainDBKey() as a key.
     */
@@ -160,7 +154,7 @@ public:
     * Returns usage of the domain and optionaly by any subdomain.
     */
   nsresult
-  GetUsage(const nsACString& aDomain, bool aIncludeSubDomains, PRInt32 *aUsage);
+  GetUsage(const nsACString& aDomain, bool aIncludeSubDomains, PRInt32 *aUsage, bool aPrivate);
 
   /**
    * Marks the storage as "cached" after the DOMStorageImpl object has loaded