Remove all blimp engine code

blimp/engine/app/test_content_main_delegate.h

-// 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.
-
-#ifndef BLIMP_ENGINE_APP_TEST_CONTENT_MAIN_DELEGATE_H_
-#define BLIMP_ENGINE_APP_TEST_CONTENT_MAIN_DELEGATE_H_
-
-#include <memory>
-
-#include "base/macros.h"
-#include "blimp/engine/app/blimp_content_main_delegate.h"
-
-namespace blimp {
-namespace engine {
-
-class TestContentMainDelegate : public BlimpContentMainDelegate {
- public:
-  TestContentMainDelegate();
-  ~TestContentMainDelegate() override;
-
-  static TestContentMainDelegate* GetInstance();
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(TestContentMainDelegate);
-};
-
-}  // namespace engine
-}  // namespace blimp
-
-#endif  // BLIMP_ENGINE_APP_TEST_CONTENT_MAIN_DELEGATE_H_