Make hiding a frame with display:none really hide the docshell all the way.

Bug 308182, r=biesi, sr=jst

docshell/base/nsDocShell.cpp

@@ -3820,12 +3820,12 @@ nsDocShell::SetVisibility(PRBool aVisibility)
     if (!mContentViewer)
         return NS_OK;
     if (aVisibility) {
-        NS_ENSURE_SUCCESS(EnsureContentViewer(), NS_ERROR_FAILURE);
         mContentViewer->Show();
     }
-    else if (mContentViewer)
+    else {
         mContentViewer->Hide();
-
+    }
+    
     return NS_OK;
 }
 

layout/generic/nsFrameFrame.cpp

@@ -571,11 +571,20 @@ nsSubDocumentFrame::Destroy(nsPresContext* aPresContext)
         // can safely go away when this frame is destroyed.
 
         content_viewer->SetSticky(PR_FALSE);
-
-        // Hide the content viewer now that the frame is going away...
-
-        content_viewer->Hide();
       }
+
+      nsCOMPtr<nsIBaseWindow> baseWin = do_QueryInterface(docShell);
+      NS_ASSERTION(baseWin, "Docshell must be an nsIBaseWindow");
+
+      // Now reverse the steps we took in ShowDocShell().  But don't call
+      // Destroy(); that will be handled by destroying our frame loader, if
+      // needed.
+
+      // Hide the content viewer now that the frame is going away...
+      baseWin->SetVisibility(PR_FALSE);
+
+      // Clear out the parentWidget, since it's about to die with us
+      baseWin->SetParentWidget(nsnull);
     }
   }