--- a/docshell/base/nsIDocShellTreeOwner.idl
+++ b/docshell/base/nsIDocShellTreeOwner.idl
@@ -18,21 +18,19 @@ interface nsIDocShellTreeOwner : nsISupp
 {
 	/**
 	 * Called when a content shell is added to the docshell tree.  This is
 	 * _only_ called for "root" content shells (that is, ones whose parent is a
 	 * chrome shell).
 	 *
 	 * @param aContentShell the shell being added.
 	 * @param aPrimary whether the shell is primary.
-	 * @param aID the "id" of the shell.  What this actually means is
-	 *			undefined. Don't rely on this for anything.
 	 */
 	void contentShellAdded(in nsIDocShellTreeItem aContentShell,
-	                       in boolean aPrimary, in AString aID);
+	                       in boolean aPrimary);
 
 	/**
 	 * Called when a content shell is removed from the docshell tree.  This is
 	 * _only_ called for "root" content shells (that is, ones whose parent is a
 	 * chrome shell).  Note that if aContentShell was never added,
 	 * contentShellRemoved should just do nothing.
 	 *
 	 * @param aContentShell the shell being removed.

--- a/dom/base/nsFrameLoader.cpp
+++ b/dom/base/nsFrameLoader.cpp
@@ -956,17 +956,17 @@ nsFrameLoader::AddTreeItemToTreeOwner(ns
   if (aParentType == nsIDocShellTreeItem::typeChrome && isContent) {
     retval = true;
 
     bool is_primary = value.LowerCaseEqualsLiteral("content-primary");
 
     if (aOwner) {
       mOwnerContent->AddMutationObserver(this);
       mObservingOwnerContent = true;
-      aOwner->ContentShellAdded(aItem, is_primary, value);
+      aOwner->ContentShellAdded(aItem, is_primary);
     }
   }
 
   return retval;
 }
 
 static bool
 AllDescendantsOfType(nsIDocShellTreeItem* aParentItem, int32_t aType)
@@ -3279,17 +3279,17 @@ nsFrameLoader::AttributeChanged(nsIDocum
   }
 #endif
 
   parentTreeOwner->ContentShellRemoved(mDocShell);
   if (value.LowerCaseEqualsLiteral("content") ||
       StringBeginsWith(value, NS_LITERAL_STRING("content-"),
                        nsCaseInsensitiveStringComparator())) {
 
-    parentTreeOwner->ContentShellAdded(mDocShell, is_primary, value);
+    parentTreeOwner->ContentShellAdded(mDocShell, is_primary);
   }
 }
 
 /**
  * Send the RequestNotifyAfterRemotePaint message to the current Tab.
  */
 NS_IMETHODIMP
 nsFrameLoader::RequestNotifyAfterRemotePaint()

--- a/embedding/browser/nsDocShellTreeOwner.cpp
+++ b/embedding/browser/nsDocShellTreeOwner.cpp
@@ -269,20 +269,20 @@ nsDocShellTreeOwner::EnsureContentTreeOw
 
   if (mWebBrowser) {
     mContentTreeOwner->WebBrowser(mWebBrowser);
   }
 }
 
 NS_IMETHODIMP
 nsDocShellTreeOwner::ContentShellAdded(nsIDocShellTreeItem* aContentShell,
-                                       bool aPrimary, const nsAString& aID)
+                                       bool aPrimary)
 {
   if (mTreeOwner)
-    return mTreeOwner->ContentShellAdded(aContentShell, aPrimary, aID);
+    return mTreeOwner->ContentShellAdded(aContentShell, aPrimary);
 
   EnsureContentTreeOwner();
   aContentShell->SetTreeOwner(mContentTreeOwner);
 
   if (aPrimary) {
     mPrimaryContentShell = aContentShell;
     mPrimaryTabParent = nullptr;
   }

--- a/xpfe/appshell/nsChromeTreeOwner.cpp
+++ b/xpfe/appshell/nsChromeTreeOwner.cpp
@@ -134,20 +134,20 @@ NS_IMETHODIMP nsChromeTreeOwner::GetInte
 }
 
 //*****************************************************************************
 // nsChromeTreeOwner::nsIDocShellTreeOwner
 //*****************************************************************************   
 
 NS_IMETHODIMP
 nsChromeTreeOwner::ContentShellAdded(nsIDocShellTreeItem* aContentShell,
-                                     bool aPrimary, const nsAString& aID)
+                                     bool aPrimary)
 {
   NS_ENSURE_STATE(mXULWindow);
-  return mXULWindow->ContentShellAdded(aContentShell, aPrimary, aID);
+  return mXULWindow->ContentShellAdded(aContentShell, aPrimary);
 }
 
 NS_IMETHODIMP
 nsChromeTreeOwner::ContentShellRemoved(nsIDocShellTreeItem* aContentShell)
 {
   NS_ENSURE_STATE(mXULWindow);
   return mXULWindow->ContentShellRemoved(aContentShell);
 }

--- a/xpfe/appshell/nsContentTreeOwner.cpp
+++ b/xpfe/appshell/nsContentTreeOwner.cpp
@@ -167,20 +167,20 @@ NS_IMETHODIMP nsContentTreeOwner::GetInt
 }
 
 //*****************************************************************************
 // nsContentTreeOwner::nsIDocShellTreeOwner
 //*****************************************************************************   
 
 NS_IMETHODIMP
 nsContentTreeOwner::ContentShellAdded(nsIDocShellTreeItem* aContentShell,
-                                      bool aPrimary, const nsAString& aID)
+                                      bool aPrimary)
 {
   NS_ENSURE_STATE(mXULWindow);
-  return mXULWindow->ContentShellAdded(aContentShell, aPrimary, aID);
+  return mXULWindow->ContentShellAdded(aContentShell, aPrimary);
 }
 
 NS_IMETHODIMP
 nsContentTreeOwner::ContentShellRemoved(nsIDocShellTreeItem* aContentShell)
 {
   NS_ENSURE_STATE(mXULWindow);
   return mXULWindow->ContentShellRemoved(aContentShell);
 }

--- a/xpfe/appshell/nsIXULWindow.idl
+++ b/xpfe/appshell/nsIXULWindow.idl
@@ -47,26 +47,16 @@ interface nsIXULWindow : nsISupports
    * primaryTabParent.
    */
   readonly attribute nsITabParent primaryTabParent;
 
   void tabParentAdded(in nsITabParent aTab, in boolean aPrimary);
   void tabParentRemoved(in nsITabParent aTab);
 
   /**
-   * The content shell specified by the supplied id.
-   *
-   * Note that this is a docshell tree item and therefore can not be assured of
-   * what object it is.  It could be an editor, a docshell, or a browser object.
-   * Or down the road any other object that supports being a DocShellTreeItem
-   * Query accordingly to determine the capabilities.
-   */
-  nsIDocShellTreeItem getContentShellById(in wstring ID);
-
-  /**
    * Tell this window that it has picked up a child XUL window
    * @param aChild the child window being added
    */
   void addChildWindow(in nsIXULWindow aChild);
 
   /**
    * Tell this window that it has lost a child XUL window
    * @param aChild the child window being removed

--- a/xpfe/appshell/nsWebShellWindow.cpp
+++ b/xpfe/appshell/nsWebShellWindow.cpp
@@ -617,17 +617,16 @@ nsWebShellWindow::OnStateChange(nsIWebPr
   if (cv) {
     nsCOMPtr<nsIDOMDocument> menubarDOMDoc(do_QueryInterface(cv->GetDocument()));
     if (menubarDOMDoc)
       LoadNativeMenus(menubarDOMDoc, mWindow);
   }
 #endif // USE_NATIVE_MENUS
 
   OnChromeLoaded();
-  LoadContentAreas();
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsWebShellWindow::OnLocationChange(nsIWebProgress *aProgress,
                                    nsIRequest *aRequest,
                                    nsIURI *aURI,
@@ -652,91 +651,16 @@ nsWebShellWindow::OnSecurityChange(nsIWe
                                    nsIRequest *aRequest,
                                    uint32_t state)
 {
   NS_NOTREACHED("notification excluded in AddProgressListener(...)");
   return NS_OK;
 }
 
 
-//----------------------------------------
-
-// if the main document URL specified URLs for any content areas, start them loading
-void nsWebShellWindow::LoadContentAreas() {
-
-  nsAutoString searchSpec;
-
-  // fetch the chrome document URL
-  nsCOMPtr<nsIContentViewer> contentViewer;
-  // yes, it's possible for the docshell to be null even this early
-  // see bug 57514.
-  if (mDocShell)
-    mDocShell->GetContentViewer(getter_AddRefs(contentViewer));
-  if (contentViewer) {
-    nsIDocument* doc = contentViewer->GetDocument();
-    if (doc) {
-      nsIURI* mainURL = doc->GetDocumentURI();
-
-      nsCOMPtr<nsIURL> url = do_QueryInterface(mainURL);
-      if (url) {
-        nsAutoCString search;
-        url->GetQuery(search);
-
-        AppendUTF8toUTF16(search, searchSpec);
-      }
-    }
-  }
-
-  // content URLs are specified in the search part of the URL
-  // as <contentareaID>=<escapedURL>[;(repeat)]
-  if (!searchSpec.IsEmpty()) {
-    int32_t     begPos,
-                eqPos,
-                endPos;
-    nsString    contentAreaID,
-                contentURL;
-    char        *urlChar;
-    nsresult rv;
-    for (endPos = 0; endPos < (int32_t)searchSpec.Length(); ) {
-      // extract contentAreaID and URL substrings
-      begPos = endPos;
-      eqPos = searchSpec.FindChar('=', begPos);
-      if (eqPos < 0)
-        break;
-
-      endPos = searchSpec.FindChar(';', eqPos);
-      if (endPos < 0)
-        endPos = searchSpec.Length();
-      searchSpec.Mid(contentAreaID, begPos, eqPos-begPos);
-      searchSpec.Mid(contentURL, eqPos+1, endPos-eqPos-1);
-      endPos++;
-
-      // see if we have a docshell with a matching contentAreaID
-      nsCOMPtr<nsIDocShellTreeItem> content;
-      rv = GetContentShellById(contentAreaID.get(), getter_AddRefs(content));
-      if (NS_SUCCEEDED(rv) && content) {
-        nsCOMPtr<nsIWebNavigation> webNav(do_QueryInterface(content));
-        if (webNav) {
-          urlChar = ToNewCString(contentURL);
-          if (urlChar) {
-            nsUnescape(urlChar);
-            contentURL.AssignWithConversion(urlChar);
-            webNav->LoadURI(contentURL.get(),
-                          nsIWebNavigation::LOAD_FLAGS_NONE,
-                          nullptr,
-                          nullptr,
-                          nullptr);
-            free(urlChar);
-          }
-        }
-      }
-    }
-  }
-}
-
 /**
  * ExecuteCloseHandler - Run the close handler, if any.
  * @return true iff we found a close handler to run.
  */
 bool nsWebShellWindow::ExecuteCloseHandler()
 {
   /* If the event handler closes this window -- a likely scenario --
      things get deleted out of order without this death grip.

--- a/xpfe/appshell/nsWebShellWindow.h
+++ b/xpfe/appshell/nsWebShellWindow.h
@@ -65,17 +65,16 @@ public:
   virtual void WindowActivated() override;
   virtual void WindowDeactivated() override;
 
 protected:
   friend class mozilla::WebShellWindowTimerCallback;
   
   virtual ~nsWebShellWindow();
 
-  void                     LoadContentAreas();
   bool                     ExecuteCloseHandler();
   void                     ConstrainToOpenerScreen(int32_t* aX, int32_t* aY);
 
   nsCOMPtr<nsITimer>      mSPTimer;
   mozilla::Mutex          mSPTimerLock;
 
   void        SetPersistenceTimer(uint32_t aDirtyFlags);
   void        FirePersistenceTimer();

--- a/xpfe/appshell/nsXULWindow.cpp
+++ b/xpfe/appshell/nsXULWindow.cpp
@@ -339,35 +339,16 @@ nsXULWindow::TabParentRemoved(nsITabPare
 NS_IMETHODIMP
 nsXULWindow::GetPrimaryTabParent(nsITabParent** aTab)
 {
   nsCOMPtr<nsITabParent> tab = mPrimaryTabParent;
   tab.forget(aTab);
   return NS_OK;
 }
 
-NS_IMETHODIMP nsXULWindow::GetContentShellById(const char16_t* aID, 
-   nsIDocShellTreeItem** aDocShellTreeItem)
-{
-  NS_ENSURE_ARG_POINTER(aDocShellTreeItem);
-  *aDocShellTreeItem = nullptr;
-
-  uint32_t count = mContentShells.Length();
-  for (uint32_t i = 0; i < count; i++) {
-    nsContentShellInfo* shellInfo = mContentShells.ElementAt(i);
-    if (shellInfo->id.Equals(aID)) {
-      *aDocShellTreeItem = nullptr;
-      if (shellInfo->child)
-        CallQueryReferent(shellInfo->child.get(), aDocShellTreeItem);
-      return NS_OK;
-    }
-  }
-  return NS_ERROR_FAILURE;
-}
-
 NS_IMETHODIMP nsXULWindow::AddChildWindow(nsIXULWindow *aChild)
 {
   // we're not really keeping track of this right now
   return NS_OK;
 }
 
 NS_IMETHODIMP nsXULWindow::RemoveChildWindow(nsIXULWindow *aChild)
 {
@@ -505,23 +486,16 @@ NS_IMETHODIMP nsXULWindow::Destroy()
    
   mDOMWindow = nullptr;
   if (mDocShell) {
     nsCOMPtr<nsIBaseWindow> shellAsWin(do_QueryInterface(mDocShell));
     shellAsWin->Destroy();
     mDocShell = nullptr; // this can cause reentrancy of this function
   }
 
-  // Remove our ref on the content shells
-  uint32_t count = mContentShells.Length();
-  for (uint32_t i = 0; i < count; i++) {
-    nsContentShellInfo* shellInfo = mContentShells.ElementAt(i);
-    delete shellInfo;
-  }
-  mContentShells.Clear();
   mPrimaryContentShell = nullptr;
 
   if (mContentTreeOwner) {
     mContentTreeOwner->XULWindow(nullptr);
     NS_RELEASE(mContentTreeOwner);
   }
   if (mPrimaryContentTreeOwner) {
     mPrimaryContentTreeOwner->XULWindow(nullptr);
@@ -1680,38 +1654,18 @@ nsXULWindow::GetWindowDOMElement() const
 
   const nsIDocument* document = cv->GetDocument();
   NS_ENSURE_TRUE(document, nullptr);
 
   return document->GetRootElement();
 }
 
 nsresult nsXULWindow::ContentShellAdded(nsIDocShellTreeItem* aContentShell,
-   bool aPrimary, const nsAString& aID)
+   bool aPrimary)
 {
-  nsContentShellInfo* shellInfo = nullptr;
-
-  uint32_t i, count = mContentShells.Length();
-  nsWeakPtr contentShellWeak = do_GetWeakReference(aContentShell);
-  for (i = 0; i < count; i++) {
-    nsContentShellInfo* info = mContentShells.ElementAt(i);
-    if (info->id.Equals(aID)) {
-      // We already exist. Do a replace.
-      info->child = contentShellWeak;
-      shellInfo = info;
-    }
-    else if (info->child == contentShellWeak)
-      info->child = nullptr;
-  }
-
-  if (!shellInfo) {
-    shellInfo = new nsContentShellInfo(aID, contentShellWeak);
-    mContentShells.AppendElement(shellInfo);
-  }
-    
   // Set the default content tree owner
   if (aPrimary) {
     NS_ENSURE_SUCCESS(EnsurePrimaryContentTreeOwner(), NS_ERROR_FAILURE);
     aContentShell->SetTreeOwner(mPrimaryContentTreeOwner);
     mPrimaryContentShell = aContentShell;
     mPrimaryTabParent = nullptr;
   }
   else {
@@ -1724,27 +1678,16 @@ nsresult nsXULWindow::ContentShellAdded(
   return NS_OK;
 }
 
 nsresult nsXULWindow::ContentShellRemoved(nsIDocShellTreeItem* aContentShell)
 {
   if (mPrimaryContentShell == aContentShell) {
     mPrimaryContentShell = nullptr;
   }
-
-  int32_t i, count = mContentShells.Length();
-  for (i = count - 1; i >= 0; --i) {
-    nsContentShellInfo* info = mContentShells.ElementAt(i);
-    nsCOMPtr<nsIDocShellTreeItem> curItem = do_QueryReferent(info->child);
-    if (!curItem || SameCOMIdentity(curItem, aContentShell)) {
-      mContentShells.RemoveElementAt(i);
-      delete info;
-    }
-  }
-
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsXULWindow::GetPrimaryContentSize(int32_t* aWidth,
                                    int32_t* aHeight)
 {
   if (mPrimaryTabParent) {
@@ -2266,25 +2209,8 @@ nsXULWindow::GetTabCount(uint32_t* aResu
   if (mXULBrowserWindow) {
     return mXULBrowserWindow->GetTabCount(aResult);
   }
 
   *aResult = 0;
   return NS_OK;
 }
 
-//*****************************************************************************
-//*** nsContentShellInfo: Object Management
-//*****************************************************************************   
-
-nsContentShellInfo::nsContentShellInfo(const nsAString& aID,
-                                       nsIWeakReference* aContentShell)
-  : id(aID),
-    child(aContentShell)
-{
-  MOZ_COUNT_CTOR(nsContentShellInfo);
-}
-
-nsContentShellInfo::~nsContentShellInfo()
-{
-  MOZ_COUNT_DTOR(nsContentShellInfo);
-   //XXX Set Tree Owner to null if the tree owner is nsXULWindow->mContentTreeOwner
-} 

--- a/xpfe/appshell/nsXULWindow.h
+++ b/xpfe/appshell/nsXULWindow.h
@@ -101,18 +101,17 @@ protected:
    void       SyncAttributesToWidget();
    NS_IMETHOD SavePersistentAttributes();
 
    NS_IMETHOD GetWindowDOMWindow(mozIDOMWindowProxy** aDOMWindow);
    mozilla::dom::Element* GetWindowDOMElement() const;
 
    // See nsIDocShellTreeOwner for docs on next two methods
    nsresult ContentShellAdded(nsIDocShellTreeItem* aContentShell,
-                              bool aPrimary,
-                              const nsAString& aID);
+                              bool aPrimary);
    nsresult ContentShellRemoved(nsIDocShellTreeItem* aContentShell);
    NS_IMETHOD GetPrimaryContentSize(int32_t* aWidth,
                                     int32_t* aHeight);
    NS_IMETHOD SetPrimaryContentSize(int32_t aWidth,
                                     int32_t aHeight);
    nsresult GetRootShellSize(int32_t* aWidth,
                              int32_t* aHeight);
    nsresult SetRootShellSize(int32_t aWidth,
@@ -141,17 +140,16 @@ protected:
    nsCOMPtr<nsIWidget>     mWindow;
    nsCOMPtr<nsIDocShell>   mDocShell;
    nsCOMPtr<nsPIDOMWindowOuter>  mDOMWindow;
    nsCOMPtr<nsIWeakReference> mParentWindow;
    nsCOMPtr<nsIPrompt>     mPrompter;
    nsCOMPtr<nsIAuthPrompt> mAuthPrompter;
    nsCOMPtr<nsIXULBrowserWindow> mXULBrowserWindow;
    nsCOMPtr<nsIDocShellTreeItem> mPrimaryContentShell;
-   nsTArray<nsContentShellInfo*> mContentShells; // array of doc shells by id
    nsresult                mModalStatus;
    bool                    mContinueModalLoop;
    bool                    mDebuting;       // being made visible right now
    bool                    mChromeLoaded; // True when chrome has loaded
    bool                    mShowAfterLoad;
    bool                    mIntrinsicallySized; 
    bool                    mCenterAfterLoad;
    bool                    mIsHiddenWindow;
@@ -173,25 +171,9 @@ protected:
    nsCOMPtr<nsITabParent> mPrimaryTabParent;
 private:
    nsresult GetPrimaryTabParentSize(int32_t* aWidth, int32_t* aHeight);
    nsresult GetPrimaryContentShellSize(int32_t* aWidth, int32_t* aHeight);
    nsresult SetPrimaryTabParentSize(int32_t aWidth, int32_t aHeight);
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsXULWindow, NS_XULWINDOW_IMPL_CID)
-
-// nsContentShellInfo
-// Used to map shell IDs to nsIDocShellTreeItems.
-
-class nsContentShellInfo
-{
-public:
-   nsContentShellInfo(const nsAString& aID,
-                      nsIWeakReference* aContentShell);
-   ~nsContentShellInfo();
-
-public:
-   nsString id; // The identifier of the content shell
-   nsWeakPtr child; // content shell (weak reference to nsIDocShellTreeItem)
-};
-
 #endif /* nsXULWindow_h__ */