Add the UtilityProcessMojoClient class and convert SafeJsonParser

content/browser/utility_process_mojo_client_impl.cc

+// Copyright 2016 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 "content/public/browser/utility_process_mojo_client_impl.h"
+
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/utility_process_host.h"
+#include "content/public/browser/utility_process_host_client.h"
+#include "content/public/common/service_registry.h"
+
+namespace content {
+
+// Takes care of starting and stopping the utility process and connecting
+// the Mojo InterfaceRequest.
+class UtilityProcessMojoClientImpl::Holder
+    : public base::RefCountedThreadSafe<Holder> {
+ public:
+  explicit Holder(const base::string16& process_name)
+      : process_name_(process_name) {}
+
+  // Starts the utility process on the IO thread.
+  void Start(const std::string& mojo_interface_name,
+             mojo::ScopedMessagePipeHandle interface_pipe) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        base::Bind(&Holder::StartOnIOThread, this, mojo_interface_name,
+                   base::Passed(&interface_pipe)));
+  }
+
+  // Shuts down the utility process.
+  void Shutdown() {
+    BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+                            base::Bind(&Holder::ShutdownOnIOThread, this));
+  }
+
+  void set_disable_sandbox() { disable_sandbox_ = true; }
+
+ private:
+  friend class base::RefCountedThreadSafe<Holder>;
+
+  ~Holder() = default;
+
+  // Starts the utility process and connects to the remote Mojo service.
+  void StartOnIOThread(const std::string& mojo_interface_name,
+                       mojo::ScopedMessagePipeHandle interface_pipe) {
+    DCHECK_CURRENTLY_ON(BrowserThread::IO);
+    utility_host_ = UtilityProcessHost::Create(nullptr, nullptr)->AsWeakPtr();
+    utility_host_->SetName(process_name_);
+    if (disable_sandbox_)
+      utility_host_->DisableSandbox();
+
+    ServiceRegistry* service_registry = utility_host_->GetServiceRegistry();
+    service_registry->ConnectToRemoteService(mojo_interface_name,
+                                             std::move(interface_pipe));
+    utility_host_->Start();

[Anand Mistry (off Chromium), 2016/06/10 11:13:54]

Ordering doesn't matter, but I think it's more logical to start the process and
then connect to the service. But again, it doesn't matter.

[Patrick Monette, 2016/06/10 18:13:23]

Done.

+  }
+
+  void ShutdownOnIOThread() {
+    DCHECK_CURRENTLY_ON(BrowserThread::IO);
+    delete utility_host_.get();
+  }
+
+  // Properties of the utility process.
+  base::string16 process_name_;
+  bool disable_sandbox_ = false;
+
+  // Checks that this class is always accessed from the same thread.
+  base::ThreadChecker thread_checker_;

[Anand Mistry (off Chromium), 2016/06/10 11:13:54]

This isn't particularly useful. The thread is only checked once.

[Patrick Monette, 2016/06/10 18:13:23]

Removed.

+
+  // Must only be accessed on the IO thread.
+  base::WeakPtr<UtilityProcessHost> utility_host_;
+
+  DISALLOW_COPY_AND_ASSIGN(Holder);
+};
+
+UtilityProcessMojoClientImpl::UtilityProcessMojoClientImpl(
+    const base::string16& process_name) {
+  holder_ = new Holder(process_name);
+}
+
+UtilityProcessMojoClientImpl::~UtilityProcessMojoClientImpl() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  holder_->Shutdown();
+}
+
+void UtilityProcessMojoClientImpl::set_disable_sandbox() {
+  holder_->set_disable_sandbox();
+}
+
+void UtilityProcessMojoClientImpl::StartImpl(
+    const std::string& mojo_interface_name,
+    mojo::ScopedMessagePipeHandle interface_pipe) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  holder_->Start(mojo_interface_name, std::move(interface_pipe));
+}
+
+}  // namespace content