Cleanup of EchoControl interface after downstream fixes

Bug: b/130016532
Change-Id: I94e92974c290e7080ab5c88fb2a91101a9856124
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158401
Reviewed-by: Per Ã…hgren <peah@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29608}
diff --git a/api/audio/echo_control.h b/api/audio/echo_control.h
index 9872889..d16c1ff 100644
--- a/api/audio/echo_control.h
+++ b/api/audio/echo_control.h
@@ -39,11 +39,7 @@
   virtual Metrics GetMetrics() const = 0;
 
   // Provides an optional external estimate of the audio buffer delay.
-  virtual void SetAudioBufferDelay(size_t delay_ms) {}
-  virtual void SetAudioBufferDelay(int delay_ms) {
-    // Default to old implementation.
-    SetAudioBufferDelay(static_cast<size_t>(delay_ms));
-  }
+  virtual void SetAudioBufferDelay(int delay_ms) = 0;
 
   // Returns wheter the signal is altered.
   virtual bool ActiveProcessing() const = 0;