Bug 1429078 - Handle the case where the subdoc view doesn't have a frame. r=miko

--HG--
extra : rebase_source : badce58f07f66a7a0146f51792463c08a75506f1

layout/painting/RetainedDisplayListBuilder.cpp

@@ -550,7 +550,7 @@ SubDocEnumCb(nsIDocument* aDocument, void* aData)
     MOZ_ASSERT(subDocView);
 
     nsIFrame* subDocFrame = subDocView->GetFrame();
-    MOZ_ASSERT(subDocFrame);
+    if (subDocFrame) {
       nsSubDocumentFrame* subdocumentFrame = do_QueryFrame(subDocFrame);
       MOZ_ASSERT(subdocumentFrame);
 
@@ -562,6 +562,7 @@ SubDocEnumCb(nsIDocument* aDocument, void* aData)
         TakeAndAddModifiedFramesFromRootFrame(data->modifiedFrames, rootFrame);
       }
     }
+  }
 
   aDocument->EnumerateSubDocuments(SubDocEnumCb, aData);
   return true;