RTCPeerConnection.addTrack and removeTrack added (behind flag)

chrome/browser/media/webrtc/webrtc_browsertest_base.h

Index: chrome/browser/media/webrtc/webrtc_browsertest_base.h
diff --git a/chrome/browser/media/webrtc/webrtc_browsertest_base.h b/chrome/browser/media/webrtc/webrtc_browsertest_base.h
index d201fb43f34d89953de753aa7083af8d8b6fc465..f24f9093d5b49b92e91885934bde23e8ad4ecb34 100644
--- a/chrome/browser/media/webrtc/webrtc_browsertest_base.h
+++ b/chrome/browser/media/webrtc/webrtc_browsertest_base.h
@@ -47,6 +47,12 @@ class WebRtcTestBase : public InProcessBrowserTest {
   static const char kUseDefaultAudioCodec[];
   static const char kUseDefaultVideoCodec[];
 
+  enum class StreamArgumentType {
+    NO_STREAM,
+    SHARED_STREAM,
+    INDIVIDUAL_STREAMS
+  };
+
  protected:
   WebRtcTestBase();
   ~WebRtcTestBase() override;
@@ -198,6 +204,11 @@ class WebRtcTestBase : public InProcessBrowserTest {
   void VerifyRtpReceivers(content::WebContents* tab,
                           base::Optional<size_t> expected_num_tracks =
                               base::Optional<size_t>()) const;
+  std::vector<std::string> CreateAndAddAudioAndVideoTrack(
+      content::WebContents* tab,
+      StreamArgumentType stream_argument_type) const;
+  void RemoveTrack(content::WebContents* tab,
+                   const std::string& track_id) const;
 
  private:
   void CloseInfoBarInTab(content::WebContents* tab_contents,