Bug 1058543 - Make page info work again in e10s (r=mconley)

browser/base/content/pageinfo/pageInfo.js

@@ -323,7 +323,7 @@ function onLoadPageInfo()
              window.arguments[0];
 
   if (!args || !args.doc) {
-    gWindow = window.opener.content;
+    gWindow = window.opener.gBrowser.selectedBrowser.contentWindowAsCPOW;
     gDocument = gWindow.document;
   }