Reland of TCRtpReceiver.getContributingSources() added.

content/renderer/media/webrtc/rtc_rtp_contributing_source.h

Index: content/renderer/media/webrtc/rtc_rtp_contributing_source.h
diff --git a/content/renderer/media/webrtc/rtc_rtp_contributing_source.h b/content/renderer/media/webrtc/rtc_rtp_contributing_source.h
new file mode 100644
index 0000000000000000000000000000000000000000..f287435e572c83f8cfdcf8bb75db170ebb2b0518
--- /dev/null
+++ b/content/renderer/media/webrtc/rtc_rtp_contributing_source.h
@@ -0,0 +1,34 @@
+// Copyright (c) 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 CONTENT_RENDERER_MEDIA_WEBRTC_RTC_RTP_CONTRIBUTING_SOURCE_H_
+#define CONTENT_RENDERER_MEDIA_WEBRTC_RTC_RTP_CONTRIBUTING_SOURCE_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/platform/WebRTCRtpContributingSource.h"
+#include "third_party/webrtc/api/rtpreceiverinterface.h"
+
+namespace content {
+
+class CONTENT_EXPORT RTCRtpContributingSource
+    : public blink::WebRTCRtpContributingSource {
+ public:
+  explicit RTCRtpContributingSource(const webrtc::RtpSource& source);
+  ~RTCRtpContributingSource() override;
+
+  blink::WebRTCRtpContributingSourceType SourceType() const override;
+  double TimestampMs() const override;
+  uint32_t Source() const override;
+
+ private:
+  const webrtc::RtpSource source_;
+
+  DISALLOW_COPY_AND_ASSIGN(RTCRtpContributingSource);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_WEBRTC_RTC_RTP_CONTRIBUTING_SOURCE_H_