Linux: Add multi-threaded message loop support (issue #2512)

tests/cefclient/browser/main_message_loop_multithreaded_gtk.h

@@ -0,0 +1,54 @@
+// Copyright (c) 2018 The Chromium Embedded Framework 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 CEF_TESTS_CEFCLIENT_BROWSER_MAIN_MESSAGE_LOOP_MULTITHREADED_GTK_H_
+#define CEF_TESTS_CEFCLIENT_BROWSER_MAIN_MESSAGE_LOOP_MULTITHREADED_GTK_H_
+#pragma once
+
+#include <queue>
+
+#include <gdk/gdk.h>
+
+#include "include/base/cef_lock.h"
+#include "include/base/cef_platform_thread.h"
+#include "tests/shared/browser/main_message_loop.h"
+
+namespace client {
+
+// Represents the main message loop in the browser process when using multi-
+// threaded message loop mode on Linux. In this mode there is no Chromium
+// message loop running on the main application thread. Instead, this
+// implementation utilizes a Glib context for running tasks.
+class MainMessageLoopMultithreadedGtk : public MainMessageLoop {
+ public:
+  MainMessageLoopMultithreadedGtk();
+  ~MainMessageLoopMultithreadedGtk();
+
+  // MainMessageLoop methods.
+  int Run() OVERRIDE;
+  void Quit() OVERRIDE;
+  void PostTask(CefRefPtr<CefTask> task) OVERRIDE;
+  bool RunsTasksOnCurrentThread() const OVERRIDE;
+
+ private:
+  static int TriggerRunTasks(void* self);
+  void RunTasks();
+  void DoQuit();
+
+  base::PlatformThreadId thread_id_;
+
+  GMainContext* main_context_;
+  GMainLoop* main_loop_;
+
+  base::Lock lock_;
+
+  // Must be protected by |lock_|.
+  std::queue<CefRefPtr<CefTask>> queued_tasks_;
+
+  DISALLOW_COPY_AND_ASSIGN(MainMessageLoopMultithreadedGtk);
+};
+
+}  // namespace client
+
+#endif  // CEF_TESTS_CEFCLIENT_BROWSER_MAIN_MESSAGE_LOOP_MULTITHREADED_GTK_H_