Let Contraints Controll Mute/Unmute Audio Local Playback For Desktop Sharing

content/renderer/media/user_media_client_impl.cc

Index: content/renderer/media/user_media_client_impl.cc
diff --git a/content/renderer/media/user_media_client_impl.cc b/content/renderer/media/user_media_client_impl.cc
index 10122a048a4468a368fd10747996b159811a8868..698fe47b1506c6a632727f60a96e58442f7c3a94 100644
--- a/content/renderer/media/user_media_client_impl.cc
+++ b/content/renderer/media/user_media_client_impl.cc
@@ -85,6 +85,18 @@ void CopyBlinkRequestToStreamControls(const blink::WebUserMediaRequest& request,
         }
       }
     }
+
+    bool exact =
+        request.audioConstraints().basic().googDisableLocalEcho.exact();
+    bool has_exact =
+        request.audioConstraints().basic().googDisableLocalEcho.hasExact();
+
+    if (has_exact) {
+      controls->disable_local_echo = exact;
+    } else {
+      controls->disable_local_echo =
+          controls->audio.stream_source != kMediaStreamSourceDesktop;
+    }
   }
   if (!request.videoConstraints().isNull()) {
     const blink::WebMediaTrackConstraintSet& video_basic =