RTCRtpReceiver.getContributingSources() added.

third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h

Index: third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h
diff --git a/third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h b/third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h
index bc47664985182b0c321569c3e5a413e6bd039a1a..ba22835f7eb291296645f9244ffaff793d099b35 100644
--- a/third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h
+++ b/third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h
@@ -5,8 +5,11 @@
 #ifndef RTCRtpReceiver_h
 #define RTCRtpReceiver_h
 
+#include <map>
+
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "modules/mediastream/MediaStreamTrack.h"
+#include "modules/peerconnection/RTCRtpContributingSource.h"
 #include "platform/heap/GarbageCollected.h"
 #include "platform/heap/Member.h"
 #include "platform/heap/Visitor.h"
@@ -24,12 +27,31 @@ class RTCRtpReceiver final : public GarbageCollectedFinalized<RTCRtpReceiver>,
   RTCRtpReceiver(std::unique_ptr<WebRTCRtpReceiver>, MediaStreamTrack*);
 
   MediaStreamTrack* track() const;
+  const HeapVector<Member<RTCRtpContributingSource>>& getContributingSources();
+
+  void updateSourcesIfNeeded();
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
+  void setContributingSourcesNeedsUpdating();
+
   std::unique_ptr<WebRTCRtpReceiver> m_receiver;
   Member<MediaStreamTrack> m_track;
+
+  // All contributing sources that have ever been returned by
+  // |getContributingSources| that are still alive. If |updateSourcesIfNeeded|
+  // encounters a source that already has an associate
+  // |RTCRtpContributingSource| it will be kept up-to-date. Garbage collected
+  // sources are automatically removed from the map.
+  HeapHashMap<uint32_t,
+              WeakMember<RTCRtpContributingSource>,
+              typename DefaultHash<uint32_t>::Hash,
+              WTF::UnsignedWithZeroKeyHashTraits<uint32_t>>
+      m_contributingSourcesBySourceId;
+  // The current contributing sources (|getContributingSources|).
+  HeapVector<Member<RTCRtpContributingSource>> m_contributingSources;
+  bool m_contributingSourcesNeedsUpdating = true;
 };
 
 }  // namespace blink