Bug 1176449 - Enter an update here to avoid assertions on startup. r=dbaron

--HG--
extra : rebase_source : 333672b991d5ad0c38b9516375366dd69f528d03

dom/xul/XULDocument.cpp

@@ -92,6 +92,7 @@
 #include "nsJSUtils.h"
 #include "mozilla/dom/URL.h"
 #include "nsIContentPolicy.h"
+#include "mozAutoDocUpdate.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -2967,10 +2968,14 @@ XULDocument::DoneWalking()
     // XXXldb This is where we should really be setting the chromehidden
     // attribute.
 
-    uint32_t count = mOverlaySheets.Length();
-    for (uint32_t i = 0; i < count; ++i) {
-        AddStyleSheet(mOverlaySheets[i]);
+    {
+        mozAutoDocUpdate updateBatch(this, UPDATE_STYLE, true);
+        uint32_t count = mOverlaySheets.Length();
+        for (uint32_t i = 0; i < count; ++i) {
+            AddStyleSheet(mOverlaySheets[i]);
+        }
     }
+
     mOverlaySheets.Clear();
 
     if (!mDocumentLoaded) {