Fix hangs in Mandoline page cycler on Linux with --enable-multiprocess.

components/html_viewer/html_document_application_delegate.h

 // Copyright 2015 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 COMPONENTS_HTML_VIEWER_HTML_DOCUMENT_APPLICATION_DELEGATE_H_
 #define COMPONENTS_HTML_VIEWER_HTML_DOCUMENT_APPLICATION_DELEGATE_H_
 
 #include <set>
 
 #include "base/macros.h"
@@ skipping 11 matching lines @@
 class HTMLDocument;
 
 // ApplicationDelegate created by the content handler for a specific url.
 class HTMLDocumentApplicationDelegate : public mojo::ApplicationDelegate,
                                         public HTMLFactory {
  public:
   HTMLDocumentApplicationDelegate(
       mojo::InterfaceRequest<mojo::Application> request,
       mojo::URLResponsePtr response,
       GlobalState* global_state,
-      scoped_ptr<mojo::AppRefCount> parent_app_refcount);
+      scoped_ptr<mojo::AppRefCount> parent_app_refcount,
+      const mojo::Callback<void()>& destruct_callback);
 
   void set_html_factory(HTMLFactory* factory) { html_factory_ = factory; }
   HTMLFactory* html_factory() { return html_factory_; }
 
  private:
   class ServiceConnectorQueue;
 
   ~HTMLDocumentApplicationDelegate() override;
 
   // Callback from the quit closure. We key off this rather than
@@ skipping 26 matching lines @@
   mojo::URLLoaderFactoryPtr url_loader_factory_;
   mojo::URLResponsePtr initial_response_;
   GlobalState* global_state_;
 
   // As we create HTMLDocuments they are added here. They are removed when the
   // HTMLDocument is deleted.
   std::set<HTMLDocument*> documents2_;
 
   HTMLFactory* html_factory_;
 
+  mojo::Callback<void()> destruct_callback_;
+
   base::WeakPtrFactory<HTMLDocumentApplicationDelegate> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(HTMLDocumentApplicationDelegate);
 };
 
 }  // namespace html_viewer
 
 #endif  // COMPONENTS_HTML_VIEWER_HTML_DOCUMENT_APPLICATION_DELEGATE_H_