Add default implementation of deprecated StartAecDump method.

Intended to enable deletion in downstream mock classes.

Tbr: kwiberg@webrtc.org
Bug: webrtc:6463
Change-Id: Iecc568c3ef6a983d21467a2b02ad61c59cac7e4e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/142231
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Alex Loiko <aleloi@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28318}
diff --git a/api/peer_connection_interface.h b/api/peer_connection_interface.h
index 0b2bfa4..c2e2f50 100644
--- a/api/peer_connection_interface.h
+++ b/api/peer_connection_interface.h
@@ -1413,7 +1413,9 @@
     return false;
   }
   // TODO(webrtc:6463): Deprecated; PlatformFile will soon be deleted.
-  virtual bool StartAecDump(rtc::PlatformFile file, int64_t max_size_bytes) = 0;
+  virtual bool StartAecDump(rtc::PlatformFile file, int64_t max_size_bytes) {
+    return false;
+  }
 
   // Stops logging the AEC dump.
   virtual void StopAecDump() = 0;