Basic display management for mus

components/mus/ws/platform_screen_impl_ozone.h

Index: components/mus/ws/platform_screen_impl_ozone.h
diff --git a/components/mus/ws/platform_screen_impl_ozone.h b/components/mus/ws/platform_screen_impl_ozone.h
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+++ b/components/mus/ws/platform_screen_impl_ozone.h
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+// 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 COMPONENTS_MUS_WS_PLATFORM_SCREEN_IMPL_OZONE_H_
+#define COMPONENTS_MUS_WS_PLATFORM_SCREEN_IMPL_OZONE_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "components/mus/ws/platform_screen.h"
+#include "ui/display/types/native_display_observer.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace ui {
+class NativeDisplayDelegate;
+class DisplaySnapshot;
+}
+
+namespace mus {
+namespace ws {
+
+// PlatformScreenImplOzone provides the necessary functionality to configure all
+// attached physical displays on the ozone platform.
+class PlatformScreenImplOzone : public PlatformScreen,
+                                public ui::NativeDisplayObserver {
+ public:
+  PlatformScreenImplOzone();
+  ~PlatformScreenImplOzone() override;
+
+ private:
+  // PlatformScreen
+  void Init() override;  // Must not be called until after the ozone platform is
+                         // initialized.
+  void ConfigurePhysicalDisplay(
+      const ConfiguredDisplayCallback& callback) override;
+
+  // TODO(rjkroege): NativeDisplayObserver is misnamed as it tracks changes in
+  // the physical "Screen".  Consider renaming it to NativeScreenObserver.
+  // ui::NativeDisplayObserver:
+  void OnConfigurationChanged() override;
+
+  // Some ozone platforms do not configure physical displays and so do not
+  // callback into this class via the implementation of NativeDisplayObserver.
+  // FixedSizeScreenConfiguration() short-circuits the implementation of display
+  // configuration in this case by calling the |callback| provided to
+  // ConfigurePhysicalDisplay() with a hard-coded |id| and |bounds|.
+  void FixedSizeScreenConfiguration(ConfiguredDisplayCallback callback);
+
+  // Additional display management callbacks.
+  void OnDisplaysAquired(const ConfiguredDisplayCallback& callback,
+                         const std::vector<ui::DisplaySnapshot*>& displays);
+  void OnDisplayConfigured(const ConfiguredDisplayCallback& callback,
+                           int64_t id,
+                           const gfx::Rect& bounds,
+                           bool success);
+
+  // Flags used to keep track of the current state of display configuration.
+  // |is_configuring| is true if configuring the Screen and starts false.
+  bool is_configuring_;
+
+  // If |is_configuring_| is true and another display configuration event
+  // happens, the event is deferred. |should_configure_| is set to true and a
+  // display configuration will be scheduled after the current one finishes.
+  // NB: events are handled once per vblank.
+  bool should_configure_;
+
+  std::unique_ptr<ui::NativeDisplayDelegate> native_display_delegate_;
+  ConfiguredDisplayCallback callback_;
+
+  base::WeakPtrFactory<PlatformScreenImplOzone> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PlatformScreenImplOzone);
+};
+
+}  // namespace ws
+}  // namespace mus
+
+#endif  // COMPONENTS_MUS_WS_PLATFORM_SCREEN_IMPL_OZONE_H_