--- a/third_party/WebKit/public/web/WebFrameClient.h
+++ b/third_party/WebKit/public/web/WebFrameClient.h
@@ -507,7 +507,7 @@
   // Returns string to be used as a frame id in the devtools protocol.
   // It is derived from the content's devtools_frame_token, is
   // defined by the browser and passed into Blink upon frame creation.
-  virtual WebString GetInstrumentationToken() { return ""; }
+  virtual WebString GetInstrumentationToken() { return WebString(); }
 
   // PlzNavigate
   // Called to abort a navigation that is being handled by the browser process.