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

components/html_viewer/content_handler_impl.cc

 // 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.
 
 #include "components/html_viewer/content_handler_impl.h"
 
 #include "components/html_viewer/html_document_application_delegate.h"
 
 namespace html_viewer {
 
 ContentHandlerImpl::ContentHandlerImpl(
     GlobalState* global_state,
     mojo::ApplicationImpl* app,
     mojo::InterfaceRequest<mojo::ContentHandler> request)
-    : global_state_(global_state), app_(app), binding_(this, request.Pass()) {
+    : global_state_(global_state),
+      app_(app),
+      binding_(this, request.Pass()),
+      app_refcount_(app_->app_lifetime_helper()->CreateAppRefCount()) {
 }
 
 ContentHandlerImpl::~ContentHandlerImpl() {
 }
 
 void ContentHandlerImpl::StartApplication(
     mojo::InterfaceRequest<mojo::Application> request,
-    mojo::URLResponsePtr response) {
+    mojo::URLResponsePtr response,
+    const mojo::Callback<void()>& destruct_callback) {
   // HTMLDocumentApplicationDelegate deletes itself.
   new HTMLDocumentApplicationDelegate(
       request.Pass(), response.Pass(), global_state_,
-      app_->app_lifetime_helper()->CreateAppRefCount());
+      app_->app_lifetime_helper()->CreateAppRefCount(), destruct_callback);
 }
 
 }  // namespace html_viewer