Port sky_shell to Linux for testing

sky/shell/linux/main.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 "base/at_exit.h"
+#include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/i18n/icu_util.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "sky/shell/platform_view.h"
+#include "sky/shell/service_provider.h"
+#include "sky/shell/shell.h"
+#include "sky/shell/shell_view.h"
+
+namespace sky {
+namespace shell {
+
+void Init() {
+  Shell::Init(make_scoped_ptr(new ServiceProviderContext(
+      base::MessageLoop::current()->task_runner())));
+
+  // TODO(abarth): Currently we leak the ShellView.
+  ShellView* shell_view = new ShellView(Shell::Shared());
+
+  ViewportObserverPtr viewport_observer;
+  shell_view->view()->ConnectToViewportObserver(GetProxy(&viewport_observer));
+
+  // TODO(abarth): At this point we should load some content into the view.
+  // viewport_observer->LoadURL("https://domokit.github.io/home.dart");
+}
+
+} // namespace shell
+} // namespace sky
+
+int main(int argc, const char* argv[]) {
+  base::AtExitManager exit_manager;
+  base::CommandLine::Init(argc, argv);
+
+  base::MessageLoop message_loop;
+
+  base::i18n::InitializeICU();
+
+  message_loop.PostTask(FROM_HERE, base::Bind(&sky::shell::Init));
+  message_loop.Run();
+
+  return 0;
+}