Added lots of error checking in AdjustClientXYForNestedDocuments so that things will fail gracefully while the content area is in the early stages of development (no view manager, etc). Probably fixes bug #31563.

layout/xul/base/src/nsMenuPopupFrame.cpp

@@ -267,10 +267,13 @@ nsMenuPopupFrame :: AdjustClientXYForNestedDocuments ( nsIDOMXULDocument* inPopu
   nsCOMPtr<nsIWidget> popupDocumentWidget;
   nsCOMPtr<nsIViewManager> viewManager;
   inPopupShell->GetViewManager(getter_AddRefs(viewManager));
-  nsIView* rootView;
-  viewManager->GetRootView(rootView);
-  nscoord wOffsetX, wOffsetY;
-  rootView->GetOffsetFromWidget(&wOffsetX, &wOffsetY, *getter_AddRefs(popupDocumentWidget));
+  if ( viewManager ) {  
+    nsIView* rootView;
+    viewManager->GetRootView(rootView);
+    nscoord wOffsetX, wOffsetY;
+    if ( rootView )
+      rootView->GetOffsetFromWidget(&wOffsetX, &wOffsetY, *getter_AddRefs(popupDocumentWidget));
+  }
   NS_WARN_IF_FALSE(popupDocumentWidget, "ACK, BAD WIDGET");
   
   // Find the widget associated with the target's document. Recall that we cached the
@@ -286,13 +289,20 @@ nsMenuPopupFrame :: AdjustClientXYForNestedDocuments ( nsIDOMXULDocument* inPopu
     if (targetDocument) {
       nsCOMPtr<nsIPresShell> shell ( dont_AddRef(targetDocument->GetShellAt(0)) );
       nsCOMPtr<nsIViewManager> viewManagerTarget;
-      shell->GetViewManager(getter_AddRefs(viewManagerTarget));
-      nsIView* rootViewTarget;
-      viewManagerTarget->GetRootView(rootViewTarget);
-      nscoord unusedX, unusedY;
-      rootViewTarget->GetOffsetFromWidget(&unusedX, &unusedY, *getter_AddRefs(targetDocumentWidget));
+      if ( shell ) {
+        shell->GetViewManager(getter_AddRefs(viewManagerTarget));
+        if ( viewManagerTarget ) {
+          nsIView* rootViewTarget;
+          viewManagerTarget->GetRootView(rootViewTarget);
+          if ( rootViewTarget ) {
+            nscoord unusedX, unusedY;
+            rootViewTarget->GetOffsetFromWidget(&unusedX, &unusedY, *getter_AddRefs(targetDocumentWidget));
+          }
+        }
+      }
     }
   }
+  NS_WARN_IF_FALSE(targetDocumentWidget, "ACK, BAD TARGET");
 
   // the offset we need is the difference between the upper left corner of the two widgets. Use
   // screen coordinates to find the global offset between them.