components: Add Exosphere component.

components/exo/surface.h

Index: components/exo/surface.h
diff --git a/components/exo/surface.h b/components/exo/surface.h
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+++ b/components/exo/surface.h
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+// 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 COMPONENTS_EXO_SURFACE_H_
+#define COMPONENTS_EXO_SURFACE_H_
+
+#include <list>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "third_party/skia/include/core/SkRegion.h"
+#include "ui/compositor/compositor_observer.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/views/view.h"
+
+namespace base {
+namespace trace_event {
+class TracedValue;
+}
+}
+
+namespace exo {
+class Buffer;
+class SurfaceDelegate;
+
+// This class represents a rectangular area that is displayed on the screen.
+// It has a location, size and pixel contents.
+class Surface : public views::View, public ui::CompositorObserver {
+ public:
+  Surface();
+  ~Surface() override;
+
+  // Set a buffer as the content of this surface. A buffer can only be attached
+  // to one surface at a time.
+  void Attach(Buffer* buffer);
+
+  // Describe the regions where the pending buffer is different from the
+  // current surface contents, and where the surface therefore needs to be
+  // repainted.
+  void Damage(const gfx::Rect& rect);
+
+  // Request notification when the next frame is displayed. Useful for
+  // throttling redrawing operations, and driving animations.
+  using FrameCallback = base::Callback<void(base::TimeTicks frame_time)>;
+  void RequestFrameCallback(const FrameCallback& callback);
+
+  // This sets the region of the surface that contains opaque content.
+  void SetOpaqueRegion(const SkRegion& region);
+
+  // Surface state (damage regions, attached buffers, etc.) is double-buffered.
+  // A Commit() call atomically applies all pending state, replacing the
+  // current state.
+  void Commit();
+
+  // Set the surface delegate.
+  void SetSurfaceDelegate(SurfaceDelegate* delegate);
+
+  // Returns a trace value representing the state of the surface.
+  scoped_refptr<base::trace_event::TracedValue> AsTracedValue() const;
+
+  bool HasPendingDamageForTesting() const { return !pending_damage_.IsEmpty(); }
+
+  // Overridden from views::View:
+  gfx::Size GetPreferredSize() const override;
+
+  // Overridden from ui::CompositorObserver:
+  void OnCompositingDidCommit(ui::Compositor* compositor) override;
+  void OnCompositingStarted(ui::Compositor* compositor,
+                            base::TimeTicks start_time) override;
+  void OnCompositingEnded(ui::Compositor* compositor) override {}
+  void OnCompositingAborted(ui::Compositor* compositor) override {}
+  void OnCompositingLockStateChanged(ui::Compositor* compositor) override {}
+  void OnCompositingShuttingDown(ui::Compositor* compositor) override;
+
+ private:
+  // The buffer that will become the content of surface when Commit() is called.
+  base::WeakPtr<Buffer> pending_buffer_;
+
+  // The damage region to schedule paint for when Commit() is called.
+  // TODO(reveman): Use SkRegion here after adding a version of
+  // ui::Layer::SchedulePaint that takes a SkRegion.
+  gfx::Rect pending_damage_;
+
+  // These lists contains the callbacks to notify the client when it is a good
+  // time to start producing a new frame. These callbacks move to
+  // |frame_callbacks_| when Commit() is called. Later they are moved to
+  // |active_frame_callbacks_| when the effect of the Commit() is reflected in
+  // the compositor's active layer tree. The callbacks fire once we're notified
+  // that the compositor started drawing that active layer tree.
+  std::list<FrameCallback> pending_frame_callbacks_;
+  std::list<FrameCallback> frame_callbacks_;
+  std::list<FrameCallback> active_frame_callbacks_;
+
+  // The opaque region to take effect when Commit() is called.
+  SkRegion pending_opaque_region_;
+
+  // The compsitor being observer or null if not observing a compositor.
+  ui::Compositor* compositor_;
+
+  // This can be set to have some functions delegated. E.g. ShellSurface class
+  // can set this to handle Commit() and apply any double buffered state it
+  // maintains.
+  SurfaceDelegate* delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(Surface);
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_SURFACE_H_