components: Add Exosphere component.

components/exo/buffer.h

Index: components/exo/buffer.h
diff --git a/components/exo/buffer.h b/components/exo/buffer.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_BUFFER_H_
+#define COMPONENTS_EXO_BUFFER_H_
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "gpu/command_buffer/common/mailbox.h"
+#include "gpu/command_buffer/common/sync_token.h"
+#include "ui/gfx/buffer_types.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace base {
+namespace trace_event {
+class TracedValue;
+}
+}
+
+namespace cc {
+class SingleReleaseCallback;
+class TextureMailbox;
+}
+
+namespace gfx {
+class GpuMemoryBuffer;
+}
+
+namespace exo {
+
+// This class provides the content for a Surface. The mechanism by which a
+// client provides and updates the contents is the responsibility of the client
+// and not defined as part of this class.
+class Buffer : public base::SupportsWeakPtr<Buffer> {
+ public:
+  Buffer(scoped_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer,
+         unsigned texture_target);
+  ~Buffer();
+
+  // Set the callback to run when the buffer is no longer used by the
+  // compositor. The client is free to re-use or destroy this buffer and
+  // its backing storage after this has been called.
+  void set_release_callback(const base::Closure& release_callback) {
+    release_callback_ = release_callback;
+  }
+
+  // This function can be used to acquire a texture mailbox that is bound to
+  // the buffer. Returns a release callback on success. The release callback
+  // must be called before a new texture mailbox can be acquired.
+  scoped_ptr<cc::SingleReleaseCallback> AcquireTextureMailbox(
+      cc::TextureMailbox* mailbox);
+
+  // Returns the size of the buffer.
+  gfx::Size GetSize() const;
+
+  // Returns a trace value representing the state of the buffer.
+  scoped_refptr<base::trace_event::TracedValue> AsTracedValue() const;
+
+ private:
+  static void Release(base::WeakPtr<Buffer> buffer,
+                      unsigned texture_target,
+                      unsigned texture_id,
+                      unsigned image_id,
+                      const gpu::SyncToken& sync_token,
+                      bool is_lost);
+
+  scoped_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer_;
+  const unsigned texture_target_;
+  unsigned texture_id_;
+  unsigned image_id_;
+  gpu::Mailbox mailbox_;
+  base::Closure release_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(Buffer);
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_BUFFER_H_