Add the UtilityProcessMojoClient class and convert SafeJsonParser

content/public/browser/utility_process_mojo_client.h

+// 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.
+
+#ifndef CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_MOJO_CLIENT_H_
+#define CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_MOJO_CLIENT_H_
+
+#include "base/callback.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/strings/string16.h"
+#include "base/threading/thread_checker.h"
+#include "content/public/browser/utility_process_mojo_client_impl.h"
+#include "mojo/public/cpp/bindings/interface_ptr.h"
+
+namespace content {
+
+// Implements a client to a mojo service running on a utility process. Takes
+// care of starting the utility process and connecting to the remote mojo
+// service. The utility process is terminated in the destructor.
+// Note: This class is not thread-safe. It is bound to the
+// SingleThreadTaskRunner it is created on.
+template <class MojoInterface>
+class UtilityProcessMojoClient {
+ public:
+  UtilityProcessMojoClient(const base::string16& process_name,
+                           const base::Closure& on_error_callback)
+      : impl_(process_name), on_error_callback_(on_error_callback) {
+    DCHECK(!on_error_callback_.is_null());
+  }
+
+  void set_disable_sandbox() { impl_.set_disable_sandbox(); }
+
+  void Start() {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    DCHECK(!start_called_);
+
+    start_called_ = true;
+
+    mojo::InterfaceRequest<MojoInterface> req = mojo::GetProxy(&service_);
+
+    service_.set_connection_error_handler(on_error_callback_);
+    impl_.Start(MojoInterface::Name_, req.PassMessagePipe());
+  }
+
+  // Returns the Mojo service used to make calls to the utility process.
+  MojoInterface* service() WARN_UNUSED_RESULT {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    DCHECK(start_called_);
+
+    return service_.get();
+  }
+
+ private:
+  // Called when a connection error happens or if the process didn't start.
+  base::Closure on_error_callback_;
+
+  mojo::InterfacePtr<MojoInterface> service_;
+  UtilityProcessMojoClientImpl impl_;
+
+  // Enforce calling Start() before getting the service.
+  bool start_called_ = false;
+
+  // Checks that this class is always accessed from the same thread.
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(UtilityProcessMojoClient);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_MOJO_CLIENT_H_