MockDataChannelImpl: Implement new interface methods as NOTIMPLEMENTED()

content/renderer/media/mock_data_channel_impl.h

Index: content/renderer/media/mock_data_channel_impl.h
diff --git a/content/renderer/media/mock_data_channel_impl.h b/content/renderer/media/mock_data_channel_impl.h
index 0b763dc77e627bdaf7f9336ed525bcd288ffd4b2..fa43ba7b46a848b147d1cf9afbac9de16a573347 100644
--- a/content/renderer/media/mock_data_channel_impl.h
+++ b/content/renderer/media/mock_data_channel_impl.h
@@ -30,6 +30,10 @@ class MockDataChannel : public webrtc::DataChannelInterface {
   bool negotiated() const override;
   int id() const override;
   DataState state() const override;
+  uint32_t messages_sent() const override;
+  uint64_t bytes_sent() const override;
+  uint32_t messages_received() const override;
+  uint64_t bytes_received() const override;
   uint64_t buffered_amount() const override;
   void Close() override;
   bool Send(const webrtc::DataBuffer& buffer) override;