fix typos in comments

BUG=none

Change-Id: I3e500213a7a272b6422db35575389b368c0e3ef2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176131
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Per Ã…hgren <peah@webrtc.org>
Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
Cr-Commit-Position: refs/heads/master@{#31380}
diff --git a/audio/audio_send_stream.cc b/audio/audio_send_stream.cc
index cdeea1a..62ca514 100644
--- a/audio/audio_send_stream.cc
+++ b/audio/audio_send_stream.cc
@@ -646,7 +646,7 @@
     }
   }
 
-  // Wrap the encoder in a an AudioEncoderCNG, if VAD is enabled.
+  // Wrap the encoder in an AudioEncoderCNG, if VAD is enabled.
   if (spec.cng_payload_type) {
     AudioEncoderCngConfig cng_config;
     cng_config.num_channels = encoder->NumChannels();
diff --git a/pc/data_channel.h b/pc/data_channel.h
index 7c7d220..9a0a0aa 100644
--- a/pc/data_channel.h
+++ b/pc/data_channel.h
@@ -84,7 +84,7 @@
   std::set<int> used_sids_;
 };
 
-// DataChannel is a an implementation of the DataChannelInterface based on
+// DataChannel is an implementation of the DataChannelInterface based on
 // libjingle's data engine. It provides an implementation of unreliable or
 // reliabledata channels. Currently this class is specifically designed to use
 // both RtpDataChannel and SctpTransport.