Deal with frame removal by content scripts

extensions/renderer/extension_frame_helper.h

Index: extensions/renderer/extension_frame_helper.h
diff --git a/extensions/renderer/extension_frame_helper.h b/extensions/renderer/extension_frame_helper.h
index a710d4f970517610fe40be239176e685b9cf89ab..147401e850b483233a6b9651f085f82427032eda 100644
--- a/extensions/renderer/extension_frame_helper.h
+++ b/extensions/renderer/extension_frame_helper.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "content/public/common/console_message_level.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "content/public/renderer/render_frame_observer_tracker.h"
@@ -29,7 +30,8 @@ class ScriptContext;
 // RenderFrame-level plumbing for extension features.
 class ExtensionFrameHelper
     : public content::RenderFrameObserver,
-      public content::RenderFrameObserverTracker<ExtensionFrameHelper> {
+      public content::RenderFrameObserverTracker<ExtensionFrameHelper>,
+      public base::SupportsWeakPtr<ExtensionFrameHelper> {
  public:
   ExtensionFrameHelper(content::RenderFrame* render_frame,
                        Dispatcher* extension_dispatcher);
@@ -61,6 +63,18 @@ class ExtensionFrameHelper
     return did_create_current_document_element_;
   }
 
+  // Called when the document element has been inserted in this frame. This
+  // method may invoke untrusted JavaScript code that invalidate the frame and
+  // this ExtensionFrameHelper.
+  void AfterDidCreateDocumentElement();
+
+  // Schedule a callback, to be run at the next AfterDidCreateDocumentElement
+  // notification. Only call this when you are certain that there will be such a
+  // notification, e.g. from RenderFrameObserver::DidCreateDocumentElement.
+  // Otherwise the callback is never invoked, or invoked for a document that you
+  // were not expecting.
+  void ScheduleAfterDidCreateDocumentElement(const base::Closure& callback);
+
  private:
   // RenderFrameObserver implementation.
   void DidCreateDocumentElement() override;
@@ -113,6 +127,9 @@ class ExtensionFrameHelper
   // Whether or not the current document element has been created.
   bool did_create_current_document_element_;
 
+  // Callbacks to be run at the next AfterDidCreateDocumentElement notification.
+  std::vector<base::Closure> document_element_created_callbacks_;
+
   DISALLOW_COPY_AND_ASSIGN(ExtensionFrameHelper);
 };