Bug 550330. Try harder to find a document with a layer manager that we can use to create our ImageContainer. r=mats

content/html/content/src/nsHTMLMediaElement.cpp

@@ -85,6 +85,7 @@
 #include "nsVideoFrame.h"
 #include "BasicLayers.h"
 #include <limits>
+#include "nsIDocShellTreeItem.h"
 
 #ifdef MOZ_OGG
 #include "nsOggDecoder.h"
@@ -1752,14 +1753,32 @@ void nsHTMLMediaElement::NotifyAutoplayDataReady()
  */
 static already_AddRefed<LayerManager> GetLayerManagerForDoc(nsIDocument* aDoc)
 {
-  while (aDoc) {
-    nsIDocument* displayDoc = aDoc->GetDisplayDocument();
+  nsIDocument* doc = aDoc;
+  nsIDocument* displayDoc = doc->GetDisplayDocument();
   if (displayDoc) {
-      aDoc = displayDoc;
-      continue;
+    doc = displayDoc;
+  }
+
+  nsIPresShell* shell = doc->GetPrimaryShell();
+  nsCOMPtr<nsISupports> container = doc->GetContainer();
+  nsCOMPtr<nsIDocShellTreeItem> docShellTreeItem = do_QueryInterface(container);
+  while (!shell && docShellTreeItem) {
+    // We may be in a display:none subdocument, or we may not have a presshell
+    // created yet.
+    // Walk the docshell tree to find the nearest container that has a presshell,
+    // and find the root widget from that.
+    nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(docShellTreeItem);
+    nsCOMPtr<nsIPresShell> presShell;
+    docShell->GetPresShell(getter_AddRefs(presShell));
+    if (presShell) {
+      shell = presShell;
+    } else {
+      nsCOMPtr<nsIDocShellTreeItem> parent;
+      docShellTreeItem->GetParent(getter_AddRefs(parent));
+      docShellTreeItem = parent;
+    }
   }
 
-    nsIPresShell* shell = aDoc->GetPrimaryShell();
   if (shell) {
     nsIFrame* rootFrame = shell->FrameManager()->GetRootFrame();
     if (rootFrame) {
@@ -1771,8 +1790,6 @@ static already_AddRefed<LayerManager> GetLayerManagerForDoc(nsIDocument* aDoc)
       }
     }
   }
-    aDoc = aDoc->GetParentDocument();
-  }
 
   nsRefPtr<LayerManager> manager = new BasicLayerManager(nsnull);
   return manager.forget();