Reland: Introduce GpuVideoDecodeAcceleratorFactory.

content/common/gpu/media/gpu_video_decode_accelerator_helpers.h

+// 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 CONTENT_COMMON_GPU_MEDIA_GPU_VIDEO_DECODE_ACCELERATOR_HELPERS_H_
+#define CONTENT_COMMON_GPU_MEDIA_GPU_VIDEO_DECODE_ACCELERATOR_HELPERS_H_
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+
+namespace gfx {
+class GLContext;
+}
+
+namespace gl {
+class GLImage;
+}
+
+namespace gpu {
+namespace gles2 {
+class GLES2Decoder;
+}
+}
+
+namespace content {
+
+// Helpers/defines for specific VideoDecodeAccelerator implementations in GPU
+// process. Which callbacks are required depends on the implementation.
+//
+// Note that these callbacks may be called more than once, and so must own/share
+// ownership of any objects bound to them.
+//
+// Unless specified otherwise, these callbacks must be executed on the GPU Child
+// thread (i.e. the thread which the VDAs are initialized on).
+
+// Return current GLContext.
+using GetGLContextCallback = base::Callback<gfx::GLContext*(void)>;
+
+// Make the applicable GL context current. To be called by VDAs before
+// executing any GL calls. Return true on success, false otherwise.
+using MakeGLContextCurrentCallback = base::Callback<bool(void)>;
+
+// Bind |image| to |client_texture_id| given |texture_target|. If
+// |can_bind_to_sampler| is true, then the image may be used as a sampler
+// directly, otherwise a copy to a staging buffer is required.
+// Return true on success, false otherwise.
+using BindGLImageCallback =
+    base::Callback<bool(uint32_t client_texture_id,
+                        uint32_t texture_target,
+                        const scoped_refptr<gl::GLImage>& image,
+                        bool can_bind_to_sampler)>;
+
+// Return a WeakPtr to a GLES2Decoder, if one is available.
+using GetGLES2DecoderCallback =
+    base::Callback<base::WeakPtr<gpu::gles2::GLES2Decoder>(void)>;
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_GPU_VIDEO_DECODE_ACCELERATOR_HELPERS_H_