Undo the checkin for bug 135811 and refix it better. Fixes bug 279495.

r=danm, sr=jst

docshell/base/nsDocShell.cpp

@@ -2089,7 +2089,7 @@ nsDocShell::FindItemWithName(const PRUnichar * aName,
 
     // This may fail, but comparing against null serves the same purpose
     nsCOMPtr<nsIDocShellTreeOwner>
-        reqAsTreeOwner(do_GetInterface(aRequestor));
+        reqAsTreeOwner(do_QueryInterface(aRequestor));
 
     if (mTreeOwner && mTreeOwner != reqAsTreeOwner) {
         return mTreeOwner->

xpfe/appshell/src/nsChromeTreeOwner.cpp

@@ -214,16 +214,21 @@ NS_IMETHODIMP nsChromeTreeOwner::FindItemWithName(const PRUnichar* aName,
      
       if(fIs_Content)
          {
-         xulWindow->GetPrimaryContentShell(getter_AddRefs(shellAsTreeItem));
-         if(shellAsTreeItem)
-            *aFoundItem = shellAsTreeItem;
+         xulWindow->GetPrimaryContentShell(aFoundItem);
          }
       else
          {
          nsCOMPtr<nsIDocShell> shell;
          xulWindow->GetDocShell(getter_AddRefs(shell));
          shellAsTreeItem = do_QueryInterface(shell);
-         if(shellAsTreeItem && (aRequestor != shellAsTreeItem.get()))
+         if (shellAsTreeItem) {
+           // Get the root tree item of same type, since roots are the only
+           // things that call into the treeowner to look for named items.
+           nsCOMPtr<nsIDocShellTreeItem> root;
+           shellAsTreeItem->GetSameTypeRootTreeItem(getter_AddRefs(root));
+           shellAsTreeItem = root;
+         }
+         if(shellAsTreeItem && aRequestor != shellAsTreeItem)
             {
             // Do this so we can pass in the tree owner as the requestor so the child knows not
             // to call back up.

xpfe/appshell/src/nsContentTreeOwner.cpp

@@ -221,16 +221,26 @@ NS_IMETHODIMP nsContentTreeOwner::FindItemWithName(const PRUnichar* aName,
             *aFoundItem = shellAsTreeItem;
             NS_ADDREF(*aFoundItem);
             }
-         else if(aRequestor != shellAsTreeItem.get())
+         else
             {
-            // Do this so we can pass in the tree owner as the requestor so the child knows not
-            // to call back up.
-            nsCOMPtr<nsIDocShellTreeOwner> shellOwner;
-            shellAsTreeItem->GetTreeOwner(getter_AddRefs(shellOwner));
-            nsCOMPtr<nsISupports> shellOwnerSupports(do_QueryInterface(shellOwner));
+            // Get the root tree item of same type, since roots are the only
+            // things that call into the treeowner to look for named items.
+            nsCOMPtr<nsIDocShellTreeItem> root;
+            shellAsTreeItem->GetSameTypeRootTreeItem(getter_AddRefs(root));
+            NS_ASSERTION(root, "Must have root tree item of same type");
+            shellAsTreeItem = root;
+            if(aRequestor != shellAsTreeItem)
+               {
+               // Do this so we can pass in the tree owner as the
+               // requestor so the child knows not to call back up.
+               nsCOMPtr<nsIDocShellTreeOwner> shellOwner;
+               shellAsTreeItem->GetTreeOwner(getter_AddRefs(shellOwner));
+               nsCOMPtr<nsISupports> shellOwnerSupports(do_QueryInterface(shellOwner));
 
-            shellAsTreeItem->FindItemWithName(aName, shellOwnerSupports,
-                                              aOriginalRequestor, aFoundItem);
+               shellAsTreeItem->FindItemWithName(aName, shellOwnerSupports,
+                                                 aOriginalRequestor,
+                                                 aFoundItem);
+               }
             }
          if(*aFoundItem)
             return NS_OK;