Remove duplicate application cpp files in mojo/application.

mojo/application/public/cpp/lib/application_test_main.cc

 // Copyright 2014 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/command_line.h"
+#include "base/test/test_timeouts.h"
+#include "mojo/application/public/cpp/application_runner.h"
 #include "mojo/application/public/cpp/application_test_base.h"
 #include "mojo/public/c/system/main.h"
-#include "mojo/public/cpp/environment/environment.h"
 
 MojoResult MojoMain(MojoHandle handle) {
-  // An Environment instance is needed to construct run loops.
-  mojo::Environment environment;
+  // An AtExitManager instance is needed to construct message loops.
+  base::AtExitManager at_exit;
+
+  // Initialize the current process Commandline and test timeouts.
+  mojo::ApplicationRunner::InitBaseCommandLine();
+  TestTimeouts::Initialize();
 
   return mojo::test::RunAllTests(handle);
-}
+}