Deal with frame removal by content scripts

extensions/renderer/extension_frame_helper.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/extension_frame_helper.h"
 
 #include "base/strings/string_util.h"
 #include "content/public/renderer/render_frame.h"
 #include "extensions/common/api/messaging/message.h"
 #include "extensions/common/constants.h"
@@ skipping 105 matching lines @@
 void ExtensionFrameHelper::DidCreateDocumentElement() {
   did_create_current_document_element_ = true;
   extension_dispatcher_->DidCreateDocumentElement(
       render_frame()->GetWebFrame());
 }
 
 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) {
   extension_dispatcher_->content_watcher()->DidMatchCSS(
       render_frame()->GetWebFrame(), newly_matching_selectors,
       stopped_matching_selectors);
 }
 
 void ExtensionFrameHelper::DidCreateScriptContext(
     v8::Local<v8::Context> context,
@@ skipping 92 matching lines @@
     const std::string& module_name,
     const std::string& function_name,
     const base::ListValue& args,
     bool user_gesture) {
   extension_dispatcher_->InvokeModuleSystemMethod(render_frame(), extension_id,
                                                   module_name, function_name,
                                                   args, user_gesture);
 }
 
 }  // namespace extensions