Fix accessibility with out-of-process iframes.

content/public/test/browser_test_utils.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_PUBLIC_TEST_BROWSER_TEST_UTILS_H_
 #define CONTENT_PUBLIC_TEST_BROWSER_TEST_UTILS_H_
 
 #include <queue>
 #include <string>
 #include <vector>
@@ skipping 386 matching lines @@
   // Callback to WebContentCreated(). Cached so that we can unregister it.
   base::Callback<void(WebContents*)> web_contents_created_callback_;
 
   WebContents* web_contents_;
   scoped_ptr<RenderViewCreatedObserver> child_observer_;
   scoped_refptr<MessageLoopRunner> runner_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsAddedObserver);
 };
 
+// This observer keeps track of the last deleted RenderViewHost to avoid
+// accessing it and causing use-after-free condition.
+class RenderViewHostDeletedObserver : public WebContentsObserver {
+ public:
+  RenderViewHostDeletedObserver(RenderViewHost* rvh);
+  ~RenderViewHostDeletedObserver() override;
+  void RenderViewDeleted(RenderViewHost* render_view_host) override;
+  bool deleted();
+  void WaitUntilDeleted();
+
+ private:
+  int process_id_;
+  int routing_id_;
+  bool deleted_;
+  scoped_ptr<base::RunLoop> runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(RenderViewHostDeletedObserver);
+};
+
+// This observer keeps track of the last deleted RenderFrameHost to avoid
+// accessing it and causing use-after-free condition.
+class RenderFrameHostDeletedObserver : public WebContentsObserver {
+ public:
+  RenderFrameHostDeletedObserver(RenderFrameHost* rfh);
+  ~RenderFrameHostDeletedObserver() override;
+  void RenderFrameDeleted(RenderFrameHost* render_frame_host) override;
+  bool deleted();
+  void WaitUntilDeleted();
+
+ private:
+  int process_id_;
+  int routing_id_;
+  bool deleted_;
+  scoped_ptr<base::RunLoop> runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(RenderFrameHostDeletedObserver);
+};
+
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_BROWSER_TEST_UTILS_H_