Bug 1572837 - Fix browser_dbg_rr_stepping-04.js.

Differential Revision: https://phabricator.services.mozilla.com/D41436

--HG--
extra : moz-landing-system : lando

devtools/client/webreplay/mochitest/browser_dbg_rr_stepping-04.js

@@ -17,9 +17,9 @@ add_task(async function() {
   const bp = await setBreakpoint(threadFront, "doc_rr_basic.html", 21);
   await rewindToLine(threadFront, 21);
   await checkEvaluateInTopFrame(target, "number", 10);
+  await waitForSelectedLocation(dbg, 21);
   await reverseStepOverToLine(threadFront, 20);
   await reverseStepOverToLine(threadFront, 12);
-  await reverseStepOverToLine(threadFront, 12);
 
   // After reverse-stepping out of the topmost frame we should rewind to the
   // last breakpoint hit.

devtools/server/actors/thread.js

@@ -1997,6 +1997,11 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
       breakpoints: this.breakpointActorMap.listKeys(),
     };
   },
+
+  logLocation: function(prefix, frame) {
+    const loc = this.sources.getFrameLocation(frame);
+    dump(`${prefix} (${loc.line}, ${loc.column})\n`);
+  },
 });
 
 Object.assign(ThreadActor.prototype.requestTypes, {