Remove all blimp engine code

blimp/engine/app/ui/blimp_screen.h

-// 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.
-
-#ifndef BLIMP_ENGINE_APP_UI_BLIMP_SCREEN_H_
-#define BLIMP_ENGINE_APP_UI_BLIMP_SCREEN_H_
-
-#include <vector>
-
-#include "base/macros.h"
-#include "base/observer_list.h"
-#include "ui/display/display.h"
-#include "ui/display/screen_base.h"
-
-namespace aura {
-class WindowTreeHost;
-}
-
-namespace blimp {
-namespace engine {
-
-// Presents the client's single screen.
-class BlimpScreen : public display::ScreenBase {
- public:
-  BlimpScreen();
-  ~BlimpScreen() override;
-
-  void set_window_tree_host(aura::WindowTreeHost* window_tree_host) {
-    window_tree_host_ = window_tree_host;
-  }
-
-  // Updates the size reported by the primary display.
-  void UpdateDisplayScaleAndSize(float scale, const gfx::Size& size);
-
-  // display::Screen implementation.
-  gfx::Point GetCursorScreenPoint() override;
-  bool IsWindowUnderCursor(gfx::NativeWindow window) override;
-  gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) override;
-  display::Display GetDisplayNearestWindow(gfx::NativeView view) const override;
-
- private:
-  aura::WindowTreeHost* window_tree_host_;
-  DISALLOW_COPY_AND_ASSIGN(BlimpScreen);
-};
-
-}  // namespace engine
-}  // namespace blimp
-
-#endif  // BLIMP_ENGINE_APP_UI_BLIMP_SCREEN_H_