diff --git a/api/frame_transformer_interface.h b/api/frame_transformer_interface.h
index fd60b87596..2f7b139f9f 100644
--- a/api/frame_transformer_interface.h
+++ b/api/frame_transformer_interface.h
@@ -60,9 +60,7 @@ class TransformableVideoFrameInterface : public TransformableFrameInterface {
 
   virtual VideoFrameMetadata Metadata() const = 0;
 
-  // TODO(https://crbug.com/webrtc/14709): Make pure virtual when Chromium MOCK
-  // has implemented this.
-  virtual void SetMetadata(const VideoFrameMetadata&) {}
+  virtual void SetMetadata(const VideoFrameMetadata&) = 0;
 };
 
 // Extends the TransformableFrameInterface to expose audio-specific information.