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

components/html_viewer/html_document_application_delegate.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/html_document_application_delegate.h"
 
 #include "base/bind.h"
 #include "components/html_viewer/global_state.h"
 #include "components/html_viewer/html_document.h"
 #include "mojo/application/public/cpp/application_connection.h"
@@ skipping 38 matching lines @@
 
   ScopedVector<Request> requests_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceConnectorQueue);
 };
 
 HTMLDocumentApplicationDelegate::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)
     : app_(this,
            request.Pass(),
            base::Bind(&HTMLDocumentApplicationDelegate::OnTerminate,
                       base::Unretained(this))),
       parent_app_refcount_(parent_app_refcount.Pass()),
       url_(response->url),
       initial_response_(response.Pass()),
       global_state_(global_state),
       html_factory_(this),
+      destruct_callback_(destruct_callback),
       weak_factory_(this) {}
 
 HTMLDocumentApplicationDelegate::~HTMLDocumentApplicationDelegate() {
   // Deleting the documents is going to trigger a callback to
   // OnHTMLDocumentDeleted() and remove from |documents_|. Copy the set so we
   // don't have to worry about the set being modified out from under us.
   std::set<HTMLDocument*> documents2(documents2_);
   for (HTMLDocument* doc : documents2)
     doc->Destroy();
   DCHECK(documents2_.empty());
+  destruct_callback_.Run();
 }
 
 // Callback from the quit closure. We key off this rather than
 // ApplicationDelegate::Quit() as we don't want to shut down the messageloop
 // when we quit (the messageloop is shared among multiple
 // HTMLDocumentApplicationDelegates).
 void HTMLDocumentApplicationDelegate::OnTerminate() {
   delete this;
 }
 
@@ skipping 87 matching lines @@
     HTMLFrame::CreateParams* params) {
   return new HTMLFrame(params);
 }
 
 HTMLWidgetRootLocal* HTMLDocumentApplicationDelegate::CreateHTMLWidgetRootLocal(
     HTMLWidgetRootLocal::CreateParams* params) {
   return new HTMLWidgetRootLocal(params);
 }
 
 }  // namespace html_viewer