Implement client-side video stream support for WebRTC-based protocol.

remoting/protocol/webrtc_video_renderer_adapter.cc

+// 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.
+
+#include "remoting/protocol/webrtc_video_renderer_adapter.h"
+
+#include <utility>
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
+#include "remoting/protocol/frame_consumer.h"
+#include "third_party/libjingle/source/talk/media/base/videoframe.h"
+#include "third_party/libyuv/include/libyuv/video_common.h"
+#include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
+
+namespace remoting {
+namespace protocol {
+
+WebrtcVideoRendererAdapter::WebrtcVideoRendererAdapter(
+    scoped_refptr<webrtc::MediaStreamInterface> media_stream,
+    FrameConsumer* frame_consumer)
+    : media_stream_(std::move(media_stream)),
+      frame_consumer_(frame_consumer),
+      output_format_fourcc_(frame_consumer_->GetPixelFormat() ==
+                                    FrameConsumer::FORMAT_BGRA
+                                ? libyuv::FOURCC_ARGB
+                                : libyuv::FOURCC_ABGR),
+      task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      weak_factory_(this) {
+  webrtc::VideoTrackVector video_tracks = media_stream_->GetVideoTracks();
+  if (video_tracks.empty()) {
+    LOG(ERROR) << "Received media stream with no video tracks.";
+    return;
+  }
+
+  video_tracks[0]->AddRenderer(this);

[Jamie, 2016/01/12 21:00:04]

Also LOG(ERROR) if there's more than 1?

[Sergey Ulanov, 2016/01/12 22:13:45]

Done.

+}
+
+WebrtcVideoRendererAdapter::~WebrtcVideoRendererAdapter() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+}
+
+void WebrtcVideoRendererAdapter::RenderFrame(const cricket::VideoFrame* frame) {
+  // TODO(sergeyu): WebRTC calls RenderFrame on a separate thread it creates.
+  // FrameConsumer normally expects to be called on the network thread, so we
+  // cannot call FrameConsumer::AllocateFrame() here and instead
+  // BasicDesktopFrame is created directly. This will not correctly with all
+  // FrameConsumer implementations. Fix this somehow.

[Jamie, 2016/01/12 21:00:04]

It doesn't need to be this CL, but why not just bounce to the correct thread?

[Sergey Ulanov, 2016/01/12 22:13:45]

Because we don't get ownership of the |frame| here, i.e. it would have to be
copied somewhere to bounce to a different thread, which is rather inefficient.
One potential solution is to keep a queue of pre-allocated frames somewhere, but
that would require to know screen size beforehand.

+  scoped_ptr<webrtc::DesktopFrame> rgb_frame(new webrtc::BasicDesktopFrame(
+      webrtc::DesktopSize(frame->GetWidth(), frame->GetHeight())));
+
+  frame->ConvertToRgbBuffer(
+      output_format_fourcc_, rgb_frame->data(),
+      std::abs(rgb_frame->stride()) * rgb_frame->size().height(),
+      rgb_frame->stride());
+  rgb_frame->mutable_updated_region()->AddRect(
+      webrtc::DesktopRect::MakeSize(rgb_frame->size()));
+  task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&WebrtcVideoRendererAdapter::DrawFrame,
+                 weak_factory_.GetWeakPtr(), base::Passed(&rgb_frame)));
+}
+
+void WebrtcVideoRendererAdapter::DrawFrame(
+    scoped_ptr<webrtc::DesktopFrame> frame) {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  frame_consumer_->DrawFrame(std::move(frame), base::Closure());
+}
+
+}  // namespace remoting
+}  // namespace protocol