media: Add GLES2DecoderHelper

media/gpu/gles2_decoder_helper.h

+// 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 MEDIA_GPU_GLES2_DECODER_HELPER_H_
+#define MEDIA_GPU_GLES2_DECODER_HELPER_H_
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "base/memory/ref_counted.h"
+#include "base/optional.h"
+#include "media/gpu/media_gpu_export.h"
+#include "ui/gl/gl_bindings.h"
+
+namespace gpu {
+struct Mailbox;
+namespace gles2 {
+class GLES2Decoder;
+class TextureRef;
+}  // namespace gles2
+}  // namespace gpu
+
+namespace media {
+
+// Utility methods to simplify working with a gpu::gles2::GLES2Decoder from
+// inside VDAs.
+class MEDIA_GPU_EXPORT GLES2DecoderHelper {
+ public:
+  static std::unique_ptr<GLES2DecoderHelper> Create(
+      gpu::gles2::GLES2Decoder* decoder);
+
+  virtual ~GLES2DecoderHelper() {}
+
+  // TODO(sandersd): Provide scoped version?
+  virtual bool MakeContextCurrent() = 0;
+
+  // Creates a texture and configures it as a video frame (linear filtering,
+  // clamp to edge, no mipmaps). The context must be current.
+  //
+  // See glTexImage2D() for parameter definitions.
+  //
+  // Returns nullptr on failure, but there are currently no failure paths.
+  virtual scoped_refptr<gpu::gles2::TextureRef> CreateTexture(
+      GLenum target,
+      GLenum internal_format,
+      GLsizei width,
+      GLsizei height,
+      GLenum format,
+      GLenum type) = 0;
+
+  // Creates a mailbox for a texture.
+  virtual gpu::Mailbox CreateMailbox(gpu::gles2::TextureRef* texture_ref) = 0;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_GPU_GLES2_DECODER_HELPER_H_