[Blimp] Refactor Blimp test engine with embedded test server and URL rewriting

blimp/engine/testing/app/test_blimp_main.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 "base/command_line.h"
+#include "blimp/engine/app/blimp_engine_config.h"
+#include "blimp/engine/testing/app/test_blimp_content_main_delegate.h"
+#include "content/public/app/content_main.h"
+
+int main(int argc, const char** argv) {
+  base::CommandLine::Init(argc, argv);
+  blimp::engine::SetCommandLineDefaults(base::CommandLine::ForCurrentProcess());
+
+  blimp::engine::TestBlimpContentMainDelegate delegate;
+  content::ContentMainParams params(&delegate);
+  params.argc = argc;
+  params.argv = argv;
+  return content::ContentMain(params);
+}