chromeos: Makes mushrome use simplified display management

ash/mus/ash_window_tree_host_mus.h

Index: ash/mus/ash_window_tree_host_mus.h
diff --git a/ash/mus/ash_window_tree_host_mus.h b/ash/mus/ash_window_tree_host_mus.h
new file mode 100644
index 0000000000000000000000000000000000000000..03056b54d15ebeac603b110b9f15a701f31c3105
--- /dev/null
+++ b/ash/mus/ash_window_tree_host_mus.h
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+// Copyright 2017 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 ASH_MUS_ASH_WINDOW_TREE_HOST_MUS_H_
+#define ASH_MUS_ASH_WINDOW_TREE_HOST_MUS_H_
+
+#include "ash/host/ash_window_tree_host.h"
+#include "ui/aura/mus/window_tree_host_mus.h"
+
+namespace ash {
+
+class TransformerHelper;
+
+// Implementation of AshWindowTreeHost for mus/mash.
+class AshWindowTreeHostMus : public AshWindowTreeHost,
+                             public aura::WindowTreeHostMus {
+ public:
+  explicit AshWindowTreeHostMus(aura::WindowTreeHostMusInitParams init_params);
+  ~AshWindowTreeHostMus() override;
+
+  // AshWindowTreeHost:
+  void ToggleFullScreen() override;
+  bool ConfineCursorToRootWindow() override;
+  void UnConfineCursor() override;
+  void SetRootWindowTransformer(
+      std::unique_ptr<RootWindowTransformer> transformer) override;
+  gfx::Insets GetHostInsets() const override;
+  aura::WindowTreeHost* AsWindowTreeHost() override;
+  void PrepareForShutdown() override;
+  void RegisterMirroringHost(AshWindowTreeHost* mirroring_ash_host) override;
+
+  // aura::WindowTreeHostMus:
+  void SetRootTransform(const gfx::Transform& transform) override;
+  gfx::Transform GetRootTransform() const override;
+  gfx::Transform GetInverseRootTransform() const override;
+  void UpdateRootWindowSizeInPixels(
+      const gfx::Size& host_size_in_pixels) override;
+
+ private:
+  std::unique_ptr<TransformerHelper> transformer_helper_;
+
+  DISALLOW_COPY_AND_ASSIGN(AshWindowTreeHostMus);
+};
+
+}  // namespace ash
+
+#endif  // ASH_MUS_ASH_WINDOW_TREE_HOST_MUS_H_