Add StreamTextureWrapper/StreamTextureWrapperImpl

content/renderer/media/android/stream_texture_wrapper_impl.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_RENDERER_MEDIA_ANDROID_STREAM_TEXTURE_WRAPPER_IMPL_H_
+#define CONTENT_RENDERER_MEDIA_ANDROID_STREAM_TEXTURE_WRAPPER_IMPL_H_
+
+#include <memory>
+
+#include "content/common/content_export.h"
+#include "content/renderer/media/android/stream_texture_factory.h"
+#include "gpu/command_buffer/common/mailbox.h"
+#include "media/base/video_frame.h"
+#include "media/blink/stream_texture_wrapper.h"
+
+namespace content {
+
+// Concrete implementation of StreamTextureWrapper. Any method can be called on
+// any thread, but additional threading considerations are listed in the
+// comments of individual methods.
+//
+// The StreamTexture is an abstraction allowing Chrome to wrap a SurfaceTexture
+// living in the GPU process. It allows VideoFrames to be created from the
+// SurfaceTexture's texture, in the Renderer process.
+//
+// The general idea behind our use of StreamTexture is as follows:
+// - We create a client GL texture in the Renderer process.
+// - We request the creation of a StreamTexture via the StreamTextureFactory,
+// passing the client texture ID. The call is sent to the GPU process via the
+// CommandBuffer. The "platform" GL texture reference associated with the client
+// texture ID is looked up in the TextureManager. A StreamTexture is then
+// created, wrapping a SurfaceTexture created from the texture reference. The
+// SurfaceTexture's OnFrameAvailable() callback is tied to StreamTexture's
+// OnFrameAvailable(), which fires an IPC accross the GPU channel.
+// - We create a StreamTextureProxy in the Renderer process which listens for
+// the IPC fired by the StreamTexture's OnFrameAvailable() callback.
+// - We bind the StreamTextureProxy's lifetime to the |compositor_task_runner_|.
+// - We wrap the client texture into a VideoFrame.
+// - When the SurfaceTexture's OnFrameAvailable() callback is fired (and routed
+// to the StreamTextureProxy living on the compositor thread), we notify
+// |client_| that a new frame is available, via the DidReceiveFrame() callback.
+//
+// TODO(tguilbert): Register the underlying SurfaceTexture for retrieval in the
+// browser process. See crbug.com/627658.
+//
+// TODO(tguilbert): Change StreamTextureProxy's interface to accept a
+// base::Closure instead of requiring a VideoFrameProvider::Client, to simplify
+// the MediaPlayerRendererHost interface. See crbug.com/631178.
+class CONTENT_EXPORT StreamTextureWrapperImpl
+    : public media::StreamTextureWrapper {
+ public:
+  static media::ScopedStreamTextureWrapper Create(
+      scoped_refptr<StreamTextureFactory> factory,
+      scoped_refptr<base::SingleThreadTaskRunner> main_task_runner);
+
+  // Creates the underlying StreamTexture, and binds |stream_texture_proxy_| to
+  // |compositor_task_runner|.
+  //
+  // Additional threading considerations:
+  //   - Can be called from any thread.
+  //   - Initialization will be posted to |main_task_runner_|.
+  //   - |init_cb| will be run on the calling thread.
+  //   - New frames will be signaled on |compositor_task_runner| via |client|'s
+  //     DidReceiveFrame() method.
+  void Initialize(
+      cc::VideoFrameProvider::Client* client,
+      const gfx::Size& natural_size,
+      scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner,
+      const base::Closure& init_cb) override;
+
+  // Should be called when the Video size changes.
+  // Can be called from any thread, but runs on |main_task_runner_|.
+  void UpdateTextureSize(const gfx::Size& natural_size) override;
+
+  // Returns the latest frame.
+  // N.B: We create a single VideoFrame at initialization time (and update it
+  // in UpdateTextureSize()), and repeatedly return it here. The underlying
+  // texture's changes are signalled via |client|'s DidReceiveFrame() callback.
+  scoped_refptr<media::VideoFrame> GetCurrentFrame() override;
+
+ private:
+  StreamTextureWrapperImpl(
+      scoped_refptr<StreamTextureFactory> factory,
+      scoped_refptr<base::SingleThreadTaskRunner> main_task_runner);
+  ~StreamTextureWrapperImpl() override;
+
+  // Destroys |this| safely on |main_task_runner_|.
+  void Destroy() override;
+
+  void InitializeOnMainThread(cc::VideoFrameProvider::Client* client,
+                              const base::Closure& init_cb);
+
+  void ReallocateVideoFrame(const gfx::Size& natural_size);
+
+  void SetCurrentFrameInternal(
+      const scoped_refptr<media::VideoFrame>& video_frame);
+
+  // Client GL texture ID allocated to the StreamTexture.
+  unsigned texture_id_;
+
+  // GL texture mailbox for |texture_id_|.
+  gpu::Mailbox texture_mailbox_;
+
+  // Stream texture ID.
+  unsigned stream_id_;
+
+  // Object for calling back the compositor thread to repaint the video when a
+  // frame is available. It should be bound to |compositor_task_runner_|.
+  ScopedStreamTextureProxy stream_texture_proxy_;
+
+  // Size of the video frames.
+  gfx::Size natural_size_;
+
+  scoped_refptr<StreamTextureFactory> factory_;
+
+  base::Lock current_frame_lock_;
+  scoped_refptr<media::VideoFrame> current_frame_;
+
+  scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;
+
+  base::WeakPtrFactory<StreamTextureWrapperImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(StreamTextureWrapperImpl);
+};
+
+}  // namespace media
+
+#endif  // CONTENT_RENDERER_MEDIA_ANDROID_STREAM_TEXTURE_WRAPPER_IMPL_H_