MediaStreamVideoSource exports current video format

This patch adds a getter to the MediaStreamVideoSource class which
returns the current video format.

The video format details are necessary during establishing of WiFi
Display session (for the capabilities negotiation with the sink).

BUG=242107

Review URL: https://codereview.chromium.org/1672713002

Cr-Commit-Position: refs/heads/master@{#380969}

4 files changed, 32 insertions, 0 deletions

diff --git a/content/public/renderer/media_stream_api.cc b/content/public/renderer/media_stream_api.cc
index 5baaa54..a1cc697 100644
--- a/content/public/renderer/media_stream_api.cc
+++ b/content/public/renderer/media_stream_api.cc
@@ -13,6 +13,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "content/renderer/media/media_stream_audio_source.h"
 #include "content/renderer/media/media_stream_video_capturer_source.h"
+#include "content/renderer/media/media_stream_video_source.h"
 #include "content/renderer/media/media_stream_video_track.h"
 #include "content/renderer/render_thread_impl.h"
 #include "third_party/WebKit/public/platform/WebMediaStream.h"
@@ -112,4 +113,17 @@ bool AddAudioTrackToMediaStream(
   return true;
 }
 
+const media::VideoCaptureFormat* GetCurrentVideoTrackFormat(
+    const blink::WebMediaStreamTrack& video_track) {
+  if (video_track.isNull())
+    return nullptr;
+
+  content::MediaStreamVideoSource* source =
+      content::MediaStreamVideoSource::GetVideoSource(video_track.source());
+  if (!source)
+    return nullptr;
+
+  return source->GetCurrentFormat();
+}
+
 }  // namespace content
diff --git a/content/public/renderer/media_stream_api.h b/content/public/renderer/media_stream_api.h
index b87c93d..907415c 100644
--- a/content/public/renderer/media_stream_api.h
+++ b/content/public/renderer/media_stream_api.h
@@ -8,10 +8,12 @@
 #include "content/common/content_export.h"
 #include "media/base/audio_capturer_source.h"
 #include "media/base/channel_layout.h"
+#include "media/base/video_capture_types.h"
 #include "media/base/video_capturer_source.h"
 
 namespace blink {
 class WebMediaStream;
+class WebMediaStreamTrack;
 }
 
 namespace content {
@@ -41,6 +43,12 @@ CONTENT_EXPORT bool AddAudioTrackToMediaStream(
     bool is_readonly,
     blink::WebMediaStream* web_media_stream);
 
+// On success returns pointer to the current format of the given video track;
+// returns nullptr on failure (if the argument is invalid or if the format
+// cannot be retrieved at the moment).
+CONTENT_EXPORT const media::VideoCaptureFormat* GetCurrentVideoTrackFormat(
+    const blink::WebMediaStreamTrack& video_track);
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_API_H_
diff --git a/content/renderer/media/media_stream_video_source.cc b/content/renderer/media/media_stream_video_source.cc
index f5e2eb1..9e4eeb9 100644
--- a/content/renderer/media/media_stream_video_source.cc
+++ b/content/renderer/media/media_stream_video_source.cc
@@ -401,6 +401,14 @@ base::SingleThreadTaskRunner* MediaStreamVideoSource::io_task_runner() const {
   return track_adapter_->io_task_runner();
 }
 
+const media::VideoCaptureFormat*
+    MediaStreamVideoSource::GetCurrentFormat() const {
+  DCHECK(CalledOnValidThread());
+  if (state_ == STARTING || state_ == STARTED)
+    return &current_format_;
+  return nullptr;
+}
+
 void MediaStreamVideoSource::DoStopSource() {
   DCHECK(CalledOnValidThread());
   DVLOG(3) << "DoStopSource()";
diff --git a/content/renderer/media/media_stream_video_source.h b/content/renderer/media/media_stream_video_source.h
index e86a7d1..027ee38 100644
--- a/content/renderer/media/media_stream_video_source.h
+++ b/content/renderer/media/media_stream_video_source.h
@@ -87,6 +87,8 @@ class CONTENT_EXPORT MediaStreamVideoSource
   // Returns the task runner where video frames will be delivered on.
   base::SingleThreadTaskRunner* io_task_runner() const;
 
+  const media::VideoCaptureFormat* GetCurrentFormat() const;
+
  protected:
   void DoStopSource() override;