diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 4cad99537d71..3570a825db69 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -2508,7 +2508,6 @@ NS_IMETHODIMP
 nsDocShell::SetSecurityUI(nsISecureBrowserUI *aSecurityUI)
 {
     mSecurityUI = aSecurityUI;
-    mSecurityUI->SetDocShell(this);
     return NS_OK;
 }
 
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index a7df668e0e3a..7deb7db39d2c 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -30,7 +30,6 @@
 #include "nsFocusManager.h"
 #include "nsFrameLoader.h"
 #include "nsIContent.h"
-#include "nsIDocShell.h"
 #include "nsIDOMApplicationRegistry.h"
 #include "nsIDOMElement.h"
 #include "nsIDOMEvent.h"
@@ -502,14 +501,6 @@ TabParent::GetState(uint32_t *aState)
   return NS_OK;
 }
 
-NS_IMETHODIMP
-TabParent::SetDocShell(nsIDocShell *aDocShell)
-{
-  NS_ENSURE_ARG(aDocShell);
-  NS_WARNING("No mDocShell member in TabParent so there is no docShell to set");
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 TabParent::GetTooltipText(nsAString & aTooltipText)
 {
diff --git a/netwerk/base/public/nsISecureBrowserUI.idl b/netwerk/base/public/nsISecureBrowserUI.idl
index fb8c00663dee..b04a0e719e80 100644
--- a/netwerk/base/public/nsISecureBrowserUI.idl
+++ b/netwerk/base/public/nsISecureBrowserUI.idl
@@ -8,13 +8,11 @@
 
 interface nsIDOMWindow;
 interface nsIDOMElement;
-interface nsIDocShell;
 
-[scriptable, uuid(e97e5688-add2-4a1d-acae-396d7702e382)]
+[scriptable, uuid(081e31e0-a144-11d3-8c7c-00609792278c)]
 interface nsISecureBrowserUI : nsISupports
 {
     void init(in nsIDOMWindow window);
-    void setDocShell(in nsIDocShell docShell);
 
     readonly attribute unsigned long state;
     readonly attribute AString tooltipText;
diff --git a/security/manager/boot/src/nsSecureBrowserUIImpl.cpp b/security/manager/boot/src/nsSecureBrowserUIImpl.cpp
index f679eb57a8cd..e4246723e9f6 100644
--- a/security/manager/boot/src/nsSecureBrowserUIImpl.cpp
+++ b/security/manager/boot/src/nsSecureBrowserUIImpl.cpp
@@ -19,7 +19,6 @@
 #include "nsIObserverService.h"
 #include "nsCURILoader.h"
 #include "nsIDocShell.h"
-#include "nsIDocShellTreeItem.h"
 #include "nsIDocument.h"
 #include "nsIPrincipal.h"
 #include "nsIDOMElement.h"
@@ -287,21 +286,12 @@ nsSecureBrowserUIImpl::MapInternalToExternalState(uint32_t* aState, lockIconStat
   if (ev && (*aState & STATE_IS_SECURE))
     *aState |= nsIWebProgressListener::STATE_IDENTITY_EV_TOPLEVEL;
 
-  nsCOMPtr<nsIDocShell> docShell = do_QueryReferent(mDocShell);
-  if (!docShell)
+  nsCOMPtr<nsPIDOMWindow> piwin = do_QueryReferent(mWindow);
+  if (!piwin)
     return NS_OK;
 
-  int32_t docShellType;
-  // For content docShell's, the mixed content security state is set on the root docShell.
-  if (NS_SUCCEEDED(docShell->GetItemType(&docShellType)) && docShellType == nsIDocShellTreeItem::typeContent) {
-    nsCOMPtr<nsIDocShellTreeItem> docShellTreeItem(do_QueryInterface(docShell));
-    nsCOMPtr<nsIDocShellTreeItem> sameTypeRoot;
-    docShellTreeItem->GetSameTypeRootTreeItem(getter_AddRefs(sameTypeRoot));
-    NS_ASSERTION(sameTypeRoot, "No document shell root tree item from document shell tree item!");
-    docShell = do_QueryInterface(sameTypeRoot);
-    if (!docShell)
-      return NS_OK;
-  }
+  nsIDocShell* docShell = piwin->GetDocShell();
+  MOZ_ASSERT(docShell);
 
   // Has a Mixed Content Load initiated in nsMixedContentBlocker?
   // If so, the state should be broken; overriding the previous state
@@ -329,14 +319,6 @@ nsSecureBrowserUIImpl::MapInternalToExternalState(uint32_t* aState, lockIconStat
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsSecureBrowserUIImpl::SetDocShell(nsIDocShell *aDocShell)
-{
-  nsresult rv;
-  mDocShell = do_GetWeakReference(aDocShell, &rv);
-  return rv;
-}
-
 NS_IMETHODIMP
 nsSecureBrowserUIImpl::GetTooltipText(nsAString& aText)
 {
diff --git a/security/manager/boot/src/nsSecureBrowserUIImpl.h b/security/manager/boot/src/nsSecureBrowserUIImpl.h
index fc614663208f..9d9975fca9e8 100644
--- a/security/manager/boot/src/nsSecureBrowserUIImpl.h
+++ b/security/manager/boot/src/nsSecureBrowserUIImpl.h
@@ -17,7 +17,6 @@
 #include "nsIStringBundle.h"
 #include "nsISecureBrowserUI.h"
 #include "nsIDocShell.h"
-#include "nsIDocShellTreeItem.h"
 #include "nsIWebProgressListener.h"
 #include "nsIFormSubmitObserver.h"
 #include "nsIURI.h"
@@ -67,7 +66,6 @@ protected:
   mozilla::ReentrantMonitor mReentrantMonitor;
   
   nsWeakPtr mWindow;
-  nsWeakPtr mDocShell;
   nsCOMPtr<nsINetUtil> mIOService;
   nsCOMPtr<nsIStringBundle> mStringBundle;
   nsCOMPtr<nsIURI> mCurrentURI;