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 40 matching lines @@
       !base::EqualsASCII(base::StringPiece16(origin.host()),
                          match_extension_id.c_str()))
     return false;
 
   if (match_window_id != extension_misc::kUnknownWindowId &&
       frame_helper->browser_window_id() != match_window_id)
     return false;
   return true;
 }
 
+// Runs every callback in |callbacks_to_be_run_and_cleared| while |frame_helper|
+// is valid, and clears |callbacks_to_be_run_and_cleared|.
+void RunCallbacksWhileFrameIsValid(
+    base::WeakPtr<ExtensionFrameHelper> frame_helper,
+    std::vector<base::Closure>* callbacks_to_be_run_and_cleared) {
+  // 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;
+  callbacks_to_be_run_and_cleared->swap(callbacks);
+  for (auto& callback : callbacks) {
+    callback.Run();
+    if (!frame_helper.get())
+      return;  // Frame and ExtensionFrameHelper invalidated by callback.
+  }
+}
+
 }  // namespace
 
 ExtensionFrameHelper::ExtensionFrameHelper(content::RenderFrame* render_frame,
                                            Dispatcher* extension_dispatcher)
     : content::RenderFrameObserver(render_frame),
       content::RenderFrameObserverTracker<ExtensionFrameHelper>(render_frame),
       view_type_(VIEW_TYPE_INVALID),
       tab_id_(-1),
       browser_window_id_(-1),
       extension_dispatcher_(extension_dispatcher),
-      did_create_current_document_element_(false) {
+      did_create_current_document_element_(false),
+      weak_ptr_factory_(this) {
   g_frame_helpers.Get().insert(this);
 }
 
 ExtensionFrameHelper::~ExtensionFrameHelper() {
   g_frame_helpers.Get().erase(this);
 }
 
 // static
 std::vector<content::RenderFrame*> ExtensionFrameHelper::GetExtensionFrames(
     const std::string& extension_id,
@@ skipping 34 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::RunScriptsAtDocumentStart() {
+  DCHECK(did_create_current_document_element_);
+  RunCallbacksWhileFrameIsValid(weak_ptr_factory_.GetWeakPtr(),
+                                &document_element_created_callbacks_);
+  // |this| might be dead by now.
+}
+
+void ExtensionFrameHelper::RunScriptsAtDocumentEnd() {
+  RunCallbacksWhileFrameIsValid(weak_ptr_factory_.GetWeakPtr(),
+                                &document_load_finished_callbacks_);
+  // |this| might be dead by now.
+}
+
+void ExtensionFrameHelper::ScheduleAtDocumentStart(
+    const base::Closure& callback) {
+  document_element_created_callbacks_.push_back(callback);
+}
+
+void ExtensionFrameHelper::ScheduleAtDocumentEnd(
+    const base::Closure& callback) {
+  document_load_finished_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