Deal with frame removal by content scripts

extensions/renderer/extension_frame_helper.cc

Index: extensions/renderer/extension_frame_helper.cc
diff --git a/extensions/renderer/extension_frame_helper.cc b/extensions/renderer/extension_frame_helper.cc
index c063f84a169ba2a5d6915b6cdc121647f9b93e2c..fd0179207be5e977cdabe1eba2ebf956bb4bfd38 100644
--- a/extensions/renderer/extension_frame_helper.cc
+++ b/extensions/renderer/extension_frame_helper.cc
@@ -123,6 +123,26 @@ void ExtensionFrameHelper::DidCreateNewDocument() {
   did_create_current_document_element_ = false;
 }
 
+void ExtensionFrameHelper::AfterDidCreateDocumentElement() {
+  DCHECK(did_create_current_document_element_);
+  base::WeakPtr<ExtensionFrameHelper> weak_self = AsWeakPtr();
+
+  // The JavaScript code can cause re-entrancy. To avoid a deadlock, don't run
+  // callbacks that are added during the iteration.
+  std::vector<base::Closure> callbacks;
+  document_element_created_callbacks_.swap(callbacks);
+  for (auto& callback : callbacks) {
+    callback.Run();
+    if (!weak_self.get())
+      return;  // Frame and |this| invalidated by callback.
+  }
+}
+
+void ExtensionFrameHelper::ScheduleAfterDidCreateDocumentElement(
+    const base::Closure& callback) {
+  document_element_created_callbacks_.push_back(callback);
+}
+
 void ExtensionFrameHelper::DidMatchCSS(
     const blink::WebVector<blink::WebString>& newly_matching_selectors,
     const blink::WebVector<blink::WebString>& stopped_matching_selectors) {