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

blimp/engine/testing/app/blimp_content_main_delegate_for_test.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 <memory>
+
+#include "blimp/engine/testing/app/blimp_content_browser_client_for_test.h"
+#include "blimp/engine/testing/app/blimp_content_main_delegate_for_test.h"
+
+namespace blimp {
+namespace engine {
+
+BlimpContentMainDelegateForTest::BlimpContentMainDelegateForTest() {}
+
+content::ContentBrowserClient*
+BlimpContentMainDelegateForTest::CreateContentBrowserClient() {
+  std::unique_ptr<BlimpContentBrowserClient> browser_client_for_test =
+      base::MakeUnique<BlimpContentBrowserClientForTest>();
+  content::ContentBrowserClient* client_ptr = browser_client_for_test.get();
+  BlimpContentMainDelegate::SetContentBrowserClientForTesting(
+      std::move(browser_client_for_test));
+  return client_ptr;
+}
+
+}  // namespace engine
+}  // namespace blimp